Interpretation of aerial photographs and linear measurements from them. Interpretation - aerial photographs Methods for interpreting aerial photographs
Interpretation of aerial photographs consists of recognizing photographic images of terrain objects, determining their characteristics and drawing them in accepted symbols. When deciphering, direct or constant deciphering features are used (shape, size, tone, structure of the image of objects) and indirect features that appear in the relationship between objects (mutual position, granularity of the AFS, shadow, color, etc.) The combination of these connections allows one to draw logical conclusions on object identification.
According to purpose, decryption is divided into:
1. Topographical: identify, study the situation and terrain.
2. Special, engineering: identify and study those objects and terrain elements that are most important for solving assigned problems.
Among the various decryption methods, the fastest and least expensive is the office method. The most labor-intensive and expensive is the field one. The combination of desk and field methods is called combined interpretation.
During engineering surveys, interpretation is one of the most effective means of determining topographical, engineering-geological, forestry, hydrogeological and other characteristics of the area.
The terrain can be most fully deciphered using large-scale images: the larger the scale, the more objects and their details can be identified during deciphering.
In the decoding process, a stereoscopic terrain model and various optical measuring instruments with magnification up to 10 times are widely used. The use of electronics and automation increases the objectivity and productivity of decryption work.
Decoding is carried out in the following order: settlements, social and industrial facilities, road networks, communication and power lines, hydrogeography, vegetation cover, soils, swamps.
Characteristic features of the image of terrain objects on the AFS:
a) Settlements - a system of quadrangles, lines of roads (streets), vegetable gardens.
b) Arable land - straightness of borders and different tonality of the image depending on the type of crop and time of year.
c) Railways - perpendicularity of intersections with highways. Large-scale photographs show rails, sleepers, power grid masts, etc.
d) Highways - the smoothness of turns, the uniqueness of their connection with other roads.
e) Dirt roads - light, winding lines, sometimes bordered by black stripes (ditches).
f) Power and communication lines - by shadows from poles and masts, by images of flaws - spots, unplowed areas of land near poles and masts. In forested areas, all power lines and communications have straight clearings.
g) Rivers are winding strips of varying thickness and tone density. The streams easily stand out due to their meandering nature.
h) Lakes and ponds are monochromatic surfaces bounded by closed curved contours.
i) Forests, bushes - sharply defined granular surface. The crown of deciduous trees is rounded, that of pine is jagged, and that of spruce and larch is pointed.
j) The boundaries of swamps - according to the degree of suppression of trees in the forest.
k) Terrain - by the nature of the image of the hydraulic network, by the shadow and degree of illumination of the slopes.
m) Points of the reference geodetic network - according to the configuration of the plot of land alienated to them, according to the type of point and its shadow.
Office topographic interpretation of AFS is carried out using topographic maps of scales 1:10000 - 1:25000. The results of decoding are drawn on a wax stencil applied to the APSn. The necessary numerical characteristics of objects and explanatory captions are taken from the topographic map. An example of the presentation of decryption results is given in Fig. 1
Depending on the place of production, decoding is divided into field and office.
Field interpretation produced directly on the ground by comparing an aerial photograph with nature. The field interpretation method is the most reliable, but requires a lot of time, effort and money.
Qualitative and quantitative characteristics of objects (road surface material, width of a river or road, height of trees, average distance between trees, etc.) are determined during field work. The heights of objects are measured directly using a rod (tape) or determined analytically by measuring vertical angles and subsequent calculations.
In the studied areas, as well as when updating maps, field interpretation is carried out after desk interpretation, in the order of its refinement and control, while simultaneously determining characteristics that cannot be obtained from aerial photographs.
In areas insufficiently provided with cartographic materials, as well as during aerial photo-topographic survey of poorly studied areas, field interpretation is first performed, and then desk interpretation.
The field interpretation stage is performed in the field. It begins with searching the terrain for easily identifiable objects (road intersections, free-standing buildings, trees) and orientation, i.e. aerial photograph references. If old photographs are used, some objects that exist in the contour may not be depicted on them.
As facts accumulate, the need arises to register them. For this purpose, different methods are used: drawing up diagrams, sketching, taking notes, taking photographs, or, most often, all together. Each of these recording methods has its own advantages and features, but it is important that all recordings are interconnected, comparable and localized in the images. If the work is carried out by several codebreakers, it is necessary to pay attention to the summary of materials.
The results of decoding are drawn either directly on the photographs, or on tracing paper or plastic superimposed on the photograph. It is advisable to draw with colored pens and as the research progresses.
Field notes are kept in a field interpretation log. This document is especially necessary for industry field interpretation and field work to create thematic maps. The log is carefully reviewed daily and changes are made accordingly.
Office decryption produced in laboratory conditions. The advantage of this method is its cost-effectiveness. In addition, the analysis of an aerial photograph is carried out under conditions that provide a more careful and detailed study of the photographic image using more complex stationary instruments. Office decoding is always carried out with the use of additional materials (reference cartographic, selected aerial photographs deciphered in situ, etc.). The disadvantage of desk interpretation is that it cannot ensure 100% completeness and reliability of the information received due to the specific nature of the terrain image on aerial photographs.
Decryption signs
Direct decoding signs.
When interpreting aerial photographs, objects are identified primarily by those properties that are directly transmitted on aerial photographs and are directly perceived by the observer. These properties are called direct decryption features. These include: shape, size, tone or color, structure (pattern), texture and shadow of the image of objects.
We will consider deciphering an aerial photograph using direct features using the example of Figure 2.
Figure 2.
Image Shape– this is the main direct deciphering sign by which the presence of an object and its properties are established. When visually deciphering, first of all, it is the outlines of objects and their shape that are distinguished.
On a planned aerial photograph, terrain objects are depicted as in plan, i.e. while maintaining the similarity of the contours of nature, but in smaller sizes, depending on the scale of the photo. Most terrain objects are recognized by the shape of the image: forests, rivers, roads, buildings, clearings in forests, canals, meadows, bridges, etc. For example, houses (1), dirt roads (2), railway (3), etc.
Image Size- a decryption feature less defined than the form. The size of the image of objects in the photograph depends on its scale. The actual size of an object can be determined by the scale of the image or by comparing the image size of the recognized object with the image size of another object using the formula:
where is the length (width) of the identified object in kind, m;
Length (width) of a known object in real life, m;
Length (width) of the identified object in the image, mm;
Length (width) of the image of a known object in the image, mm.
So, by the size of the image and shape, you can distinguish a highway (4) from a dirt road (2).
Image Tone- this is the degree of blackening of the photographic film in the corresponding place of the image of the object, and subsequently - blackening on the positive print (photograph). Different intensities of light rays reflected from photographic objects and striking the photosensitive film lead to varying degrees of blackening of the emulsion layer. This sign is not constant. An image of the same object may have a different tone depending on lighting, weather, season, etc. For example, roads photographed in summer are depicted as light ribbons, and in winter – dark. Thus, rivers, ponds (5), lakes appear dark on an aerial photograph, and dry, compacted roads (2), (4) turn out almost whitish; sparse vegetation has a dark gray tone, while dense vegetation has a darker tone (6).
Object shadows– and their images in the picture play a decisive role in recognizing objects of small size and contrast. The shadow makes it easier to judge the shape and height of an object. Some objects: power line supports, antenna masts, etc. – often recognized only by shadow.
A distinction is made between natural and falling shadows. The proper shadow is the unlit part of the surface of an object located on the side opposite to the Sun. Its own shadow emphasizes the volume of the object. A shadow cast by an object on the earth's surface is called a falling shadow. Repeaters, pipes (7), trees (8) and other tall objects are often well deciphered by falling shadows that convey the silhouette of the object.
Structure (drawing) the surface of objects and its image is a combination of several features (shape, size, tone, etc.) that form the surface of the element. For example, the appearance of the forest surface (8) is formed by tree crowns. In the picture, the image of the forest looks like a grainy structure; for continuous shrubs, it looks like a fine-grained structure (9).
Cultural landscape objects can have a geometrically correct image structure. For example, gardens - rare-grained “checkered”, plantings of industrial crops (10) - point linear, settlements (11) - block rectangular.
Indirect decryption signs.
Indirect deciphering signs, based on natural relationships between terrain objects, are manifested in the confinement of some objects to others, as well as in changes in the properties of some objects as a result of the influence of others on them. For example, in villages, residential buildings (1) are located closer to the street than non-residential ones. Roads or paths approaching the river and starting on the other side indicate the presence of a ferry or boat transport, or the presence of a horse or pedestrian ford. There is a known close relationship between forest composition and characteristics and soil moisture and type. On sandy and podzolic soils of medium and low humidity, mainly coniferous forests grow. Deciduous forests are more common on rich soils. Thus, based on the results of deciphering forest areas, one can judge the nature of the ground, soils, groundwater and other environmental elements.
1. Introduction………………………………………………………………………………3
2. Interpretation of images to create base maps of lands at a scale of 1:10000………………………………………………………………………………………...4
2.1. Objects of decoding and their characteristics………………...................4
2.2. Requirements for the type of decryption under consideration. Generalization norms…………………………………………………………………………………..10
2.3. Additional photography of unimaged objects…………………...11
2.4. Determining the private scale of an image………………………………...11
2.5. Decryption technology and control of results…………………..12
3. Interpretation of enlarged images during the inventory of personal lands……………………………………………………….15
4. Field work……………………………………………………………...17
INTRODUCTION
The purpose of the practice is to consolidate knowledge of performing decryption work, quality control of decryption results, and additional photography of unimaged objects. The practice is carried out for 1 week in the laboratory of the department of aerial photogeodesy with a one-day field trip (Moscow region, Mytishchi district, Borodino Village). To complete it, we united in a team consisting of 6 people: A. A. Zimin, N. Yu. Klevakina. , Nikolskaya V.S., Goldobina Yu.S., Gavrin D.D., Lumpov I.M.
The content of the practice is to carry out desk interpretation of contact aerial photographs of the near Moscow region to compile a basic map of the condition and use of lands; decoding of a fragment of an enlarged image (m =) of a rural settlement for inventory of household lands, field control and additional photography of objects that were not depicted and cannot be deciphered by office deciphering, selection and design of reference points.
INTERPRETING AERIAL PHOTOS
TO CREATE BASE MAPS OF 1:10000 SCALE LANDS
This type of decoding is carried out in order to create cadastral maps of inter-settlement lands on a scale of 1:10,000 and in sparsely populated regions - 1:25,000, as well as cadastral plans of settlements on a scale of 1:500...1:2000.
Basic requirements for the contour information content of cadastral maps and plans:
The volume of topographical (situational) information should provide: a sufficiently accurate spatial reference (applying on maps and plans) of special information about the lands; free orientation on the terrain when performing field work; the ability to make the right design decisions and put the project into practice;
The volume of special information should provide the correct solution to any of the listed tasks. Particular attention is paid to the correct display of the boundaries of land use, land ownership, characteristics of lands located in the mapped territory, and determination of the position of real estate on plans.
OBJECTS OF DECORDING WHEN CREATING BASE MAPS OF LANDS AT SCALE 1:10,000...1:25,000 AND THEIR SIGNS.
One of the most important objects of this type of interpretation is the boundaries of land use and land ownership, settlements and state reserve lands. From the point of view of decoding, boundaries refer to special objects. Their materialized manifestation on the ground is mainly boundary signs that serve as turning points. Only in some cases, when part of the border runs along a tract or coincides with linear topographic elements of the area, does it materialize in the form of a river bank, stream, clearing, roads, etc. Therefore, the conversation about the decipherable signs of the border itself comes down mainly to the analysis of the signs of boundary lines signs. They can appear on aerial photographs as light dots with sufficient brightness contrast between the pillar trenches and the surrounding background, and the diameter of the trenches must exceed the linear resolution of the materials being deciphered. Searching for images of boundary signs on decipherable materials should not be accidental. You need to know their approximate position. Identification is greatly simplified if the surviving boundary markers are marked (with lime, sawdust, etc.) with cross-shaped or other shaped signs before aerial photography.
Arable land is a plot of land systematically cultivated and used for crops, including crops of perennial grasses, as well as fallows. Arable land does not include hayfields and pastures plowed for the purpose of radical improvement, as well as the row spacing of gardens used for crops. The peculiarity of deciphering arable land is its differentiation according to qualitative characteristics. There are arable lands with an irrigation network, arable lands with estuary irrigation, drained (indicating the drainage method) with two-way regulation of the water regime, flooded, rainfed (in areas of irrigated agriculture), clean, littered with stones. Separately, arable land under rice crops is distinguished, greenhouses, hotbeds and greenhouses are shown. There are also household plots and individual vegetable gardens located outside settlements.
The main decipherable features of arable land are the clarity of boundaries and a certain “geometry” of the shape of the fields. For certain periods of shooting, a fairly informative sign of arable land is the texture of the image, but it is unstable over time. The tone of arable land can vary over a wide range - it changes depending on the condition of the area, the crop growing on it, the phase of development of this crop, etc.
The most likely errors in deciphering arable land: classifying some areas of arable land as fallow land and vice versa, as well as classifying hayfields and pastures plowed for the purpose of radical improvement as arable land.
Fallow lands include areas of former arable land that have not been used for more than one year (starting in the fall) for sowing agricultural crops and have not been prepared for fallow. When deciphered, the deposits are divided into clean ones, littered with stones, overgrown with shrubs, silt and forest growth, previously sown with rice, and rainfed (on irrigated areas). Separately, the deposits of estuary irrigation are shown, with an irrigation network, located in the irrigation zone, flooded and drained, indicating the drainage method.
The decoding characteristics of the deposit and arable land are very similar. The boundaries and traces of soil cultivation and, accordingly, the linear texture of the image are preserved for many years. However, over time, signs of cessation of processing appear - local blurriness of the texture, the appearance of spots in the texture (grains showing weeds and woody vegetation). An indirect sign of the deposit is that it is confined to inter-sharp gully and gulley areas, to heavily eroded areas.
Hayfields include areas whose grass is systematically used for haymaking. When deciphered, hayfields are divided into flooded, dry and swampy. All of them are divided into clean, covered with hummocks, overgrown with bushes, forest undergrowth or sparse forest, and forested. Waterlogged hayfields are divided according to the type of vegetation into those overgrown with reeds, cattails or reeds, and separately - overgrown with sedge. Particularly distinguished are irrigated hayfields, indicating the method of irrigation and drainage, as well as flooded and dry fields, which undergo radical improvement.
The shape and size of hayfield areas are uncertain, since their boundaries are the boundaries of arable land, fallow lands, forests, as well as topographical elements of the area (rivers, streams, roads, etc.). The texture varies depending on the quality characteristics of the hayfields. The greatest reliability in identifying hayfields is ensured by photography taken during the haymaking period and after it, before the hay is removed and the traces of harvesting are masked by the waste.
When deciphering hayfields, indirect signs are important: they are confined to certain natural complexes, the inability to drive livestock to the site, and the general absence of signs of systematic grazing.
Pasture is a plot of land whose grass stand is systematically used or is suitable for grazing, but is not used as hayfield and is not a fallow land. Pastures are divided into floodplain, upland and swampy, with subsequent division into clean, covered with hummocks, overgrown with bushes, forest undergrowth or sparse forest and forested. Upland pastures are divided into cultivated, radically improved, littered with stones, rocky and located on turfed sands.
In the steppe, semi-desert and desert zones, pastures are divided depending on the vegetation growing on them, water supply and seasonal use. Irrigated and drained pastures are shown separately. In pastures, fences and all special structures are deciphered.
Pastures, like hayfields, do not have clearly defined direct interpretative features. They are recognized mainly by indirect signs: position relative to settlements and, in particular, relative to livestock farms with the establishment of the possibility of driving livestock to a pasture area, the presence of many paths carved out by cattle, trampled at watering places and grass stands, the presence of special structures (corrals, sheds and so on.)-
Perennial plantings - land plots under woody shrubs or perennial herbaceous artificial plantings intended for the production of fruit and berry or technical products (tea, essential oils, hops, etc.).
Citrus gardens, subtropical fruit gardens, fruit gardens with vineyards, fruit and berry gardens, vineyards, berry gardens, as well as mulberry gardens, hop gardens, various plantations and nurseries of tree and shrub crops are classified separately. Irrigated and drained perennial plantings are distinguished, indicating the type of irrigation and drainage, as well as floodplain plantings. Gardens on personal plots are not decrypted. Collective gardens are shown as separate land uses. The buildings on them are not decipherable.
The main deciphering feature of perennial plantings is the texture of the image. If there is information about the types of plantings found in the area of interpretation work and the use of reference images, the reliability of desk recognition of plantings is quite high.
Deciphering rural settlements when creating basic land maps has its own characteristics. Legal boundaries are applied to decrypted materials if they are established and correspond to the actual boundary.
Individual buildings in a settlement, regardless of the functional purpose and characteristics of the buildings, are united quarterly by a common outline or, in case of dispersed development, divided into groups if the distance between the groups is more than 5 mm on the plan scale. Separate buildings within blocks are not deciphered.
Also, on a quarterly basis, without internal detail, household plots are shown with a conventional vegetable garden sign. From the general tracts of household lands, plots that are not transferred to individual use are distinguished. Explanatory inscriptions and symbols of their actual use are placed on the image.
The boundaries of the allocated blocks are formed by streets, squares, alleys, passages, and dead ends. When building on one side, an additional thin line is drawn to mark the street boundary along the outside of the roadway.
In settlements with dispersed development, permanent passages are shown with a conventional road sign; streets and squares are not highlighted.
Public outbuildings and their boundaries are shown separately (in black). Areas of unrelated land use (schools, hospitals, communications offices, etc.) are highlighted (in red) with a generalized display of buildings within the areas. The conditional display of public economic facilities and third-party land users is accompanied by abbreviated explanatory captions.
In a rural settlement, public agricultural lands and topographical objects are deciphered; rivers, streams, ravines, forests, bushes, parks, squares, etc.
Farmsteads, former farmsteads, outbuildings located outside the settlement (field camps, warehouses, etc.), and lands used for their maintenance are also subject to decoding. These objects are shown accompanied by explanatory captions.
The specificity of the decryption features of rural settlements, farmsteads, individual buildings and structures eliminates the possibility of confusion with other objects. Elements of a settlement (building strips, private lands, streets, squares, passages) are easily identified during desk and especially during stereoscopic observation of deciphered materials. Most public economic objects are identified with a high degree of reliability using indirect signs, for example, by the location of the object in the settlement, the functional nature of the depicted elements of the complex of structures, the image of cars, barrels and other objects on the territory of the object being deciphered.
Forests in this type of interpretation are not divided by species. Young plantings and areas under wild fruit trees are shown separately. In forests there are windbreaks, clearings, forest undergrowth, shrubs and shrubs.
Field-protective and garden-protective forest belts, protective plantings along irrigation and drainage canals, edges of ravines, banks of reservoirs, tree and shrub lining of roads and shipping canals, protective forest plantings along the bottom and slopes of ravines and on sands are subject to interpretation.
From the general forest tracts, irrigated and drained forests, swampy forests and shrubs, and cleared areas for involvement in agricultural production are distinguished.
The main decoding feature of forests and shrubs is the texture of the photographic image. Based on the nature of the texture and height of the plantings, determined by shadows or stereoscopic model, mature forests, natural forest growth, young forest plantings, woodlands, and shrubs are reliably separated. Clearings and, in many cases, forest roads are confidently identified. Swampiness of forests and shrubs is sometimes clearly visible on black-and-white and especially well on color spectrozonal aerial photographs. Indirect signs are used to determine swampiness (the nature of the terrain, the presence and nature of nearby bodies of water, etc.).
Forest belts and protective forest plantations are reliably recognized by direct signs using a stereoscope.
The deciphered materials show all roads, including those under construction. If roads have right of way, their boundaries are shown on the image. Within the boundaries, the lands located directly under the road, with ditches, embankments and excavations, as well as agricultural lands and other objects to be deciphered are shown.
For all railways, as well as for roads, one (their own) conventional sign is used. If the boundary of the right-of-way is located closer than 0.5 mm from the conventional road sign at the plan headquarters, then the boundary is not shown, but the width of the right-of-way is indicated on the interpreted materials.
All structures on the orogs are shown in general. The boundaries of stations, sidings and other road services are marked on decipherable materials based on geodetic data, and in their absence, based on the actual state.
Temporary roads in forests and agricultural lands are not decrypted.
Roads have specific direct decoding signs - on ordinary wide-area aerial photographs of the Non-Black Earth Zone they are displayed as light lines (stripes). Bridges and overpasses are deciphered using direct signs; the presence of culverts is determined indirectly by the intersection of roads with watercourses in the absence of bridges.
When interpreting hydrographic objects, they show the coastlines of all natural and artificial reservoirs, hydraulic structures (canals, open and closed sewers, ditches, ditches, above-ground and underground water pipelines in areas of irrigated agriculture, wells, watering points, etc.), as well as springs and springs. , dry ditches. Tree and shrub vegetation along the banks of reservoirs must be deciphered.
If the width of the watercourse is not expressed on a plan scale, the average width of the water surface in meters is shown at intervals of approximately 1 dm. In addition, the width of the channel service bands is shown. Along canals and ditches, shafts with a height of more than 1 m are deciphered. The right-of-way along canals is deciphered in the same way as the right-of-way along railways and highways. On rivers, canals and ditches, arrows indicate the direction of water flow.
Water bodies are deciphered with a high degree of reliability in black and white and especially reliably in color aerial photographs based on direct features. The task of plotting the coastline on decipherable materials is greatly facilitated if the aerial photography was carried out during a period when the water level in large reservoirs corresponded to the normal backwater level, and in rivers, lakes and ponds - to the average stable level in the summer. Otherwise, auxiliary materials (hydrographic projects, large-scale topographic maps) are used to solve this problem, or the coastline is drawn instrumentally in the field during the period of normal water levels in reservoirs.
The direction of flow in rivers is determined by indirect signs (the shape of islands and sediments on the shallows, the direction in which tributaries flow) or using a topographic map.
Swamps are divided into lowland, upland and transitional, with windows of clean water, areas with vegetation suitable for early mowing for livestock feed, drained areas but not used in agricultural production, peat mining and areas covered with trees and shrubs.
The main decoding feature of swamps is the texture of the image. Depending on the type of swamps, their bushiness (forest), cross-country ability and other characteristics, it is very diverse and heterogeneous. But in most cases it is quite specific. Indirect signs of swamps: confined to vast flat-horizontal areas of the terrain, the absence of traces of agricultural cultivation, the presence of country and field bypass roads, as well as the presence of peat mining, etc.
The composition of the vegetation cover of bogs under laboratory conditions is uncertain.
Lands that are not used in agricultural production are deciphered: sands, pebbles, rocky placers, bedrock outcrops, takyrs, salt marshes, areas contaminated and occupied by industrial waste, mining sites, areas with disturbed soil layers, etc.
Many of the listed objects have specific direct characteristics (tone, texture) and indirect ones (certain territorial location, natural and climatic conditions, etc.). The reliability of desk identification of some of these objects is insufficient.
Of the natural forms of relief, the following are deciphered: dry riverbeds, ravines and gullies, cliffs, screes, rocks, landslides, karst funnels, lines of sharp change in the steepness of turfed slopes, edges of beams, etc. Artificial elements of the relief are also shown: shafts, dams, sections of terraced slopes, dug-out places, mounds and pits, if their diameter and height (depth) are more than 1 m.
Most of these elements are detected and identified using a stereoscope. Topographical elements of the area are shown without their quantitative characteristics (operational characteristics of bridges, numerical parameters of the forest, depths of fords, etc.).
QUALITY REQUIREMENTS FOR THE TYPE OF DECORDING CONSIDERED. GENERALIZATION STANDARDS
When interpreting aerial photography materials to compile maps at a scale of 1:10,000 and 1:25,000, the following requirements are established for the accuracy of plotting elements of the situation (on the plan scale):
the error in drawing a clear boundary of an object relative to its image should not exceed 0.2 mm;
the deviation of the control definitions of a boundary that is not clearly defined in nature (for example, dry and swampy hayfields) should not exceed 1.5 mm;
the deviation of the control definitions of the clearly defined boundary (position) of an object instrumentally applied to the materials being deciphered should not exceed 0.3 mm.
In order to generalize information, the elements of the situation are not deciphered if their area on the plan scale does not exceed:
2 mm 2 for arable land, perennial plantings and cultivated pastures on irrigated and drained areas, as well as for other lands and non-agricultural lands interspersed with the listed lands;
4 mm2 for the same objects on non-reclaimed lands; 10 mm* days for other agricultural lands, as well as for non-agricultural lands interspersed with them;
50 mm 2 for agricultural land that differs in quality (for example, clean arable land and littered with stones), as well as the length of non-agricultural land;
100 mm* for areas of tree and shrub vegetation with different characteristics in the general area.
Lakes, ponds, hollows, pegs are deciphered regardless of their area. Islands on reservoirs are shown if their area is more than 5 mm 3 . Individual walnut and mulberry trees are shown in all cases, while the rest are shown only on arable land. Hollows on arable land are deciphered if their length on the plan scale is more than 5 mm; the length of other linear elements of the situation must exceed 10 mm.
RECORDING OBJECTS NOT PICTURED .
Some of the objects to be decrypted may not be depicted in the images. To apply these objects to decipherable materials, the simplest methods are used that provide sufficient accuracy. Image points that are clearly recognizable on the ground are used as reference points.
If there is a significant amount of pre-survey work, copies of the produced photographic plans (orthophotomaps) are deciphered. The image on them is reduced to a single, usually standard, scale. For additional photography in this option, you can use any geodetic methods while simultaneously recording the results obtained on a photographic map.
In another option, images enlarged to plan scale are deciphered. The subject to be photographed is roughly depicted on the photograph. The data for accurately applying it to the plan is recorded on the additional survey diagram (outline). The operator uses this data in computer photogrammetric processing of images.
When creating plans and maps, you can use technologies in which decrypted images are entered into a computer. In this case, the exact position of the objects being photographed must be marked on the photographs. This eliminates the possibility of using goniometric methods of additional photography and necessitates the use of private scale.
DETERMINING THE PARTIAL SCALE OF THE IMAGE.
To determine a particular scale, the measurement results of two corresponding bases in the image and terrain are used. Their ends are reliably identified points. In the photo they are pinned. The error in identification and tattooing should not exceed 0.1 mm. The size of the bases should be approximately the same as the maximum length of the lines used during finishing work. Reducing the length of the bases will reduce the accuracy of these works.
Let's consider the methodology for determining the minimum size of bases. Let us assume that decoding is carried out for subsequent work, for example, land inventory, which requires determining the scale with an accuracy of no rougher than 1/t-1/100. Obviously, the accuracy of determining the scale will depend on the accuracy of the measurement of the bases in the image - on the ground, the bases can be measured with any accuracy. The total error in identifying and marking points on the image, as well as measuring the basis, will be approximately.
Let's calculate the minimum length of the basis / in the image for the following conditions:
The use of two bases allows you to control the results of determining the scale (eliminates gross errors), identify the maximum difference in scale in different directions in the zone and evaluate the possible accuracy of performing metric actions using the average value of a particular scale. Obviously, the bases should not have common fixed points. In gyro-stabilized images, variability occurs mainly due to the influence of the terrain. Therefore, when working in such terrain, one of the bases should be placed along and the other across the main direction of the slope of the site. The bases will turn out to be approximately mutually perpendicular. If the arms are approximately symmetrical relative to their point of intersection, then the average value of the particular scale will be at this point.
On flat terrain, it is advisable to maintain the same relative position of the bases. The possible equality of scales for two bases in this case does not yet indicate that the perspective distortions of the image in this image are not significant. To determine the degree of influence of the image tilt on its different scales in the zone, a third basis with a diagonal direction relative to the main bases should be used.
The final value of the denominator of the private scale is taken as the average of two (three) definitions:
t (t1 + m2)/2
DECORDING TECHNOLOGY AND CONTROL OF RESULTS
Deciphering begins with plotting the exact position of the boundaries of the main land uses and land tenures. Let's consider the general technology for decrypting them. In this case, it may turn out that boundary markers (border turning points) have been preserved on the ground and can be reliably identified in a photograph; boundary markers have been preserved on the ground, but are not recognizable in the photograph; boundary signs on the area have not been preserved.
Deciphering borders in the first case comes down to simple identification, recording with pins and appropriate design of identified signs on decipherable materials. The implementation of this option, as already noted, is facilitated by marking signs before aerial photography.
In the second case, boundary markers are applied to a photograph in the field using geodetic techniques. To solve the same problem in office conditions, data on the position of the borders is obtained from decrypted photographs or photographic plans of previous years, if the border has not changed since then. Identification of photographic image points is performed stereoscopically or using linear notches (proportional compass) from preserved and reliably identified photographic image points,
In the third case, in the absence of coordinates of turning points, the boundary is deciphered at the direction of authorized adjacent land users in the field.
If the actual land use boundary does not correspond to the legal boundary, then both boundaries are marked on the materials being deciphered, with a corresponding note being included in the acceptance certificate of the decoding results.
Sections of boundaries that have been reliably identified under laboratory conditions are drawn in ink. The remaining sections are deciphered in the field.
The boundaries of settlements are drawn on the image according to their actual position. Recognition of boundaries is greatly simplified if they are marked on the ground by ditches, hedges, rows of trees or bushes, and coincide with roads.
If the actual border of the settlement coincides with the legal border, then on the deciphered materials they are indicated by a solid red line, otherwise, and also if there is no legal border on the ground, by a dotted line.
The boundaries of irrigated and drained lands are drawn on decipherable materials from inventory plans of reclaimed lands, from plans for their graphical recording or as-built drawings drawn up when these lands were put into operation.
When desk deciphering other objects, a full range of features is required, as well as materials collected at the preparatory stage. Decoding in most cases is carried out according to the principle of sequential transition from the general to the specific. First, the main linear topographical objects (roads, hydrographic elements) are deciphered, then the general contours of forests and agricultural lands, and then each of the selected areas is analyzed. Other variants of the decryption sequence are also used.
The names of settlements, rivers, lakes, tracts, information about the characteristics of forests, swamps, and flood boundaries are established using topographic maps.
Conventional signs of reliably identified elements of the situation are drawn in ink. Uncertainly decipherable areas (objects) that cannot be deciphered at all are highlighted in photographs and transferred to a reproduction of a block layout or photographic diagram. Based on these materials, as well as taking into account information received from local land management authorities about changes that occurred after aerial photography in the work area, routes for field revision and monitoring of the results of desk interpretation are designed.
Field work, depending on the number and density of areas in need of field survey, the overall situational density of the work area and local road conditions, is carried out by walking around or using ground and air vehicles. The latter options must be economically justified.
Along the report-free boundaries of the site, a strip outside it with a width of 1 cm on the plan scale is deciphered.
The field part of the work is carried out with the participation of an authorized representative of land use and land ownership. If necessary, farm officials and representatives of the district land management service are invited for consultation.
The results of interpretation in the field are recorded using a hard pencil or a dull needle, with the obligatory daily drawing of the results in ink. Decipherers of the State Land Cadastre Survey use colored “corrector pens” (such as felt-tip pens) to apply symbols to decipherable materials (mainly orthophotomaps). With the other end of such a pen, you can remove erroneously applied elements of the situation from the deciphered image.
Objects found in the field that are not depicted are applied to the photographic image using special techniques.
As decoding is performed, the performer coordinates (consolidates) the results along the adjacent boundaries of working areas, tablets, and farms.
In order to prevent methodological errors in decoding, the head of the department controls all stages of work, especially at the initial stage. Comments on the work and recommendations are included in the current control report.
Having completed the work, the performer forms a “Decryption File”, including in it decryption materials and documents, the list of which is established in accordance with current instructions or other regulatory guidelines.
The completed work is accepted by the work manager with a mandatory visit to the work site. At the same time, it is established that the decryption results comply with the requirements of the instructions and additional technical conditions. Attention is drawn to the implementation of the recommendations specified in the acts of current control, to the quality of drawing the results of interpretation and execution of summaries, to the availability and correctness of execution of the necessary documents. The completeness and reliability of interpretation results are controlled selectively, directly in the field, in the most difficult areas. The contractor eliminates any deficiencies found.
Project consultants indicating their respective sectionsChapter 3
INTERPRETING AERIAL PHOTOS
§ 12. BASIC DECORDING FEATURES
Identification, recognition and determination of the characteristics of objects depicted in a photograph of an area is called its decoding. It is carried out in order to collect information about the area, various objects and elements, identifying their qualitative and quantitative characteristics.
Decoding is divided into topographic and special. Topographical interpretation characterizes the situation and the relief of the earth's surface, and specially - in addition to them, those objects and terrain elements that are most important for the solution various special national economic tasks.
Interpretation of photographs reveals the prevailing natural conditions of the area in the area of the designed structure, establishes the influence of these conditions on the main technical and economic indicators of the design and construction of the structure. It is one of the most important elements in obtaining initial information about the area.
When surveying roads, airfields, bridges and tunnels, photographs are used to determine various topographic, geological, hydrogeological and hydrological conditions of the area, which influence the processes of design and construction of these structures.
The characteristic features and features of photographic images of various objects and elements of the area, contributing to their identification or disclosure of content, are called decoding signs. They can be direct and indirect. Direct features include shape, size, shadow, tone (color) and structure, brightness of the surface of the identified objects; to indirect - the relationship, interdependence, interdependence of various objects and phenomena and their accompanying characteristics that exists in nature and is reflected in photographs. For example, the relationship between relief and the resistance of soils and rocks to washout, weathering and destruction, the relationship between rocks, soils and their moisture.
When using direct decoding signs, possible deviations in the shape and size of images of individual terrain objects are taken into account, including those distortions that arise due to the influence of the inclination of photographs and the terrain, as well as changes in the phototone and coloring of images of individual terrain objects when photographing them.
When deciphering, it is taken into account that terrain objects of different nature can be represented in the photographs
4 - image brightness control; 5 - binocular; 6, 7 - scale and screw for changing magnification; 8 - longitudinal parallax scale; 9 - lens; 10 - table
the same tonality and, conversely, the same elements and objects when photographed in aerial photographs at different times and from different heights may have different tones of the images.
It can be deciphered most fully from large-scale photographs. The larger the scale, the more objects and their details can be identified during decoding. Large terrain objects are especially well deciphered in office conditions. Objects whose images are tenths and hundredths of a millimeter can be identified only by indirect signs or with the help of optical instruments, for example a magnifying glass with a magnification of approximately 5-10x, a mirror-lens stereoscope with variable magnification up to 10-15x, an interpretoscope (Fig. 12 ).
To increase the reliability of deciphering small objects, aerial photographs are sometimes enlarged, the scale of aerial photography is enlarged, or two-scale aerial photography is performed. The most effective way to enlarge images is 4-5 times, although images of a number of terrain objects can be viewed with a magnification of 10-12 times.
Indirect signs of interpretation are divided into geomorphological and geobotanical. The first are based on the relationship between relief forms and the structure of the hydraulic network with the material composition and geophysical properties of rocks and soils with the conditions of occurrence and tectonic characteristics of the territory.
rii. Geobotanical characteristics are based on the relationship of vegetation with the relief, geological structure and hydrogeological conditions of the area, on the association of vegetation with the composition of rocks and soils, with the hydrological and permafrost conditions of the area. Experts have found that soils and substrates significantly affect the composition of plants, the variability of flower and leaf color, and their shape.
Currently, botanists have discovered many indicator plants that help determine not only the composition of soils, but also minerals. The number of direct and indirect signs of decoding determines its completeness and reliability.
Interpretation is carried out on aerial photographs, or less often on photographic diagrams, by engineers and survey technicians specially trained for this purpose.
During aerial surveys of engineering structures, special interpretation is carried out, during which they establish not only the topographic, geological and hydrological content of the area, but also its influence on the technical and economic indicators of the construction of the structure being designed.
§ 13. TYPES OF DECODING AERIAL PHOTOS
Interpretation of photographs, in which the identification of objects is carried out through a desk study of photographic images, is called desk decoding. When directly identifying objects depicted on aerial photographs and their features in nature, it is called field, and with air - aerovisu - a l n y m.
Cameral decoding is performed most simply, does not depend on the natural and climatic conditions of the area, is the fastest, most productive and economical. However, in complex areas where structures are being surveyed, this method ensures the collection of information only partially, despite the fact that many objects and terrain elements are fairly confidently identified without testing on the ground.
In the process of desk interpretation, a stereoscopic terrain model, various optical measuring instruments, color, spectrozonal or multispectral images are widely used. They allow you to more clearly identify individual objects and terrain features. Recently, the results of radar or infrared aerial surveys, carried out in parallel with aerial photography, have begun to be used for interpretation.
The use of special surveys improves the quality, completeness, reliability and detail of definitions, increases their detail and objectivity, brings the quality of office survey work closer to field research, and in some cases makes it possible to disclose and obtain a number of important data about
areas that are contained in the surface layer of the Earth and are not observed on the surface. For example, due to moisture, the surface of bedrock is clearly visible on an aerial photograph through the soil layer of the arable land.
Having established by direct or indirect signs the presence of an object important for the design of a structure, they strive to confirm its presence with the help of other indirect or direct signs and provide the most complete and reliable information about it.
Therefore, when deciphering, it is necessary to have a good knowledge of not only the main features and characteristics of various terrain objects, but also their established relationships with other objects accompanying them in nature.
Field interpretation of images is the most complete and reliable, but requires a direct visit to the area and is therefore labor-intensive and expensive, highly dependent on the natural and climatic conditions of the area, and the degree of accessibility of individual places. However, the high quality of field interpretation facilitates its implementation during those periods of design and survey work when it is necessary to make final responsible engineering decisions.
IN design and survey In work, it is often beneficial to combine office and field methods of interpreting photographs. The technology of aerial survey work sharply reduces the volume of field interpretation, and, consequently, all its inherent disadvantages. Office-field interpretation is carried out mainly office-wise with partial field work on standard sections or standard routes.
IN in difficult conditions it is necessary to carry out a continuous route office-field interpretation along the accepted main version of the route.
Reference areas are selected so that they contain all the objects and terrain elements that are found on aerial photographs to be deciphered. These areas are typical in terms of the physical, geographical and morphological conditions of the area.
Office-field interpretation during surveys of transport structures allows field work to be carried out only on 10-15% of the territory to be surveyed.
The technology of office-field interpretation first involves office work, as a result of which topographic, geological and hydrogeological characteristics are established, the area where options for the designed structure are supposed to be located is divided into areas that are homogeneous in basic geophysical and geomorphological conditions, the boundaries of standard areas are established, and objects are identified , the characteristics of which are not accurately identified or areas within which there may be objects of importance
for design, but for certain reasons were not identified during decoding.
After desk interpretation, they begin field surveys of the territory of the standard areas located along the standard routes. During surveys, within such areas, the main characteristics of the area, the properties of photographic images of various objects, direct and indirect signs of their interpretation are determined. To identify the geological structure and soil and ground conditions of the area, pits and boreholes are laid in such areas, outcrops are cleared, and the necessary geophysical work is performed. The results are indicated on reference aerial photographs, in tables and interpretation logs. Aerial reference photographs, together with the obtained data, are placed in special interpretation albums or card files of reference aerial photographs. In the future, they are used for detailed desk interpretation of aerial photographs covering the area where construction options are located.
When designing linear structures, the selection of standard sections should be carried out according to the landscape principle, in which a section with a characteristic image must have the same natural and technical and economic conditions for the construction of the structure. However, to correctly identify such areas, it is necessary to create a special system of typical landscape areas during decoding. When surveying roads, the homogeneity of sites lies in the homogeneity of topographic, geological and hydrogeological conditions, established according to their inherent geophysical, botanical and geomorphological characteristics.
During office-field interpretation, work is first carried out using existing maps, and then special survey teams directly on the ground clarify the results of office work, identify objects and terrain characteristics missing from the images, and carry out geological excavations in the places identified during office-based interpretation. This method is most appropriate in difficult conditions of hard-to-reach terrain and large design objects.
10. TOPOGRAPHIC INTERPRETATION OF AERIAL IMAGES
10.1. When deciphering aerial photographs, images of topographic objects are identified and recognized, and then they are drawn with appropriate symbols.
In the process of decoding, the necessary characteristics of objects must be determined or transferred from materials of cartographic value, geographical names must be collected and established. Objects that are not depicted on aerial photographs due to their small size or insufficient contrast with the background, as well as objects that appear on the ground after aerial photography, are subject to additional photography in situ. Images of objects that disappeared after aerial photography should be crossed out with blue lines when deciphered.
The completeness and detail of interpretation are determined by the requirements for the content of topographic maps, terrain features and the scale of the map being created.
10.2. Interpretation during stereotopographic surveys is performed on photographic plans, photographic diagrams or aerial photographs. In this case, aerial photographs and photographic diagrams on which the interpretation results are recorded should be approximately brought to the scale of the map being created and printed on matte photographic paper.
If decoding is carried out before the production of photographic plans, then the aerial photographs lead to the map scale based on the photographic altitude values.
10.3. Interpretation during stereotopographic survey is carried out mainly by a combination of office and field methods. Continuous office and continuous field interpretation is also used.
The working design for decoding (for example, on photographic diagrams) should show the areas subject to continuous office and continuous field decoding, field decoding routes, observation stations and sites for creating deciphering standards should be outlined for the rest of the territory.
10.4. Continuous desk interpretation is used when within the territory of the expedition there are inaccessible and hard-to-reach areas (high mountains, impenetrable swamps, sandy massifs, etc.). The basis for decoding in this case will be geographical descriptions, maps of adjacent scales, materials and decoding standards previously produced for similar types of terrain in other areas.
Continuous field interpretation should be carried out in large populated areas and in areas where many topographic objects are concentrated that cannot be deciphered office-wise. Continuous field interpretation, especially over large areas, is advisable to perform on photographic maps.
10.5. When combining office and field (ground-based or aerial) interpretation, the sequence of work is determined by the knowledge of the survey area, the performers’ familiarity with the nature of the landscape and the availability of materials of cartographic significance.
In the studied areas, field interpretation is carried out after desk interpretation; in order to refine and control it, while simultaneously establishing characteristics that cannot be determined from aerial photographs (material of buildings, depth of wells, etc.), and collecting names.
In areas that are insufficiently provided with materials of cartographic value, first field route interpretation is carried out with observation stations and the creation of standards for interpretation of typical landscapes, and then desk interpretation is performed.
10.6. Decoding along ground routes is carried out covering a band width of about 250 m in forests and from 500 to 1000 m in open areas. At the same time, topographic objects encountered along the way are identified and recorded with simplified signs or abbreviated inscriptions and the required characteristics of the objects are determined. The terrain features identified along the route should be characterized in the form of appropriate records, sketches and photographs in order to use them in the future for office interpretation and stereo drawing of the relief.
In areas that are difficult to access or with monotonous landscapes, field ground decoding is carried out in individual areas characteristic of a given area, connected by a network of decoding routes. For each such section, a decoding standard is compiled in the form of one or two fully deciphered stereo pairs of aerial photographs with attached descriptions of the contours, as when deciphering along routes and at observation stations (see paragraph 10.7 ).
10.7. For selective detailed study of the terrain in nature and identification of natural relationships of topographic objects along the route, observation stations are selected. These stations are located in areas that are most typical for a given territory. Characteristics of the terrain and the features of its aerial photograph at these stations are given over an area of at least 4 sq. cm on the scale of the aerial photograph. Within this area, conventional signs are not drawn, but all contours that differ in tone or structure of the aerial photograph are numbered and described. At the same time, the topographer must identify the relationships between various elements of the terrain (for example, the influence of height, orientation and steepness of terrain slopes, as well as moisture conditions on changes in vegetation) and their manifestation in the nature of the aerial photograph. At observation stations, in addition, such characteristics of objects as river flow speeds, the depth of swamps, etc. are determined.
10.8. Decryption routes are laid out:
through populated areas that are not specifically designated for carrying out continuous field interpretation within their boundaries;
along main roads, power lines and communications; pipelines, river beds disguised by trees;
along the free frames of trapezoids;
in selected areas necessary for recognizing aerial photographs of vegetation and soils, studying landforms shown by symbols, etc., and determining the characteristics of deciphered objects that cannot be obtained in office conditions.
10.9. Aerovisual interpretation is performed in addition to ground-based or instead of it (especially in hard-to-reach areas). Helicopters and light aircraft are used for aerovisual interpretation. The aerovisual flight mode, subject to technical and operational conditions, is determined by the nature of the objects being deciphered and the properties of the observer. Flight altitude is recommended within 200-300 m, speed 60-75 km per hour.
10.10. Interpretation of aerial photographs from the air consists of preparatory work, in-flight observations and processing of materials.
During the preparation process, the results of preliminary desk interpretation are studied, flight routes are designed and marked on photographic diagrams, and observers are trained.
Work in flight consists of examining from the air areas that have not been deciphered cameralically and identifying objects that are not recognized on aerial photographs. The results of observations are recorded with conventional signs or pins with object numbers and recording on route or area photographic diagrams or using a tape recorder, drawing objects not depicted on aerial photographs along adjacent contours and time of flight of landmarks, as well as using a sighting palette and on-board photography.
Aerovisual interpretation along given individual routes is supplemented, if necessary, with observations from low altitudes, on turns and when the helicopter is hovering, and to create interpretation standards and obtain certain characteristics (see paragraph. 10.5 And 10.7 ) make ground observations during plantings in selected areas.
Processing of aerovisual interpretation materials with recording of its results on a photographic diagram must be carried out immediately after each flight.
10.11. Interpretation of areas located between ground or aerovisual field interpretation routes is carried out office-wise, as a rule, simultaneously with drawing the relief on universal stereophotogrammetric instruments (in the process of compiling the original map) and is carried out on an expedition or in an enterprise.
10.12. The deciphered materials must be selectively controlled along special routes by the head of the party, the editor and the leadership of the expedition.
10.13. Upon completion of interpretation, the topographer summarizes the elements of the situation along the boundaries of the working areas between adjacent aerial photographs or photographic diagrams. To facilitate reporting, these boundaries are drawn so that they do not intersect complex features, such as populated areas. Copies are made along the outer frames of the area deciphered by one performer.
10.14. As a result of the work the following must be completed:
interpreted photographic plans, photographic diagrams or aerial photographs;
lists of established names;
route interpretation logs with the attachment of ground and airborne photographs of characteristic terrain objects (with negatives).
11. EDITORIAL WORK
11.1. The purpose of editorial work carried out at all stages of topographic survey is to ensure the reliability and completeness of the content of the created maps, the geographical correctness and clarity of the image of the area, as well as the unity in the display of homogeneous objects on all trapezoids of the survey area. As a rule, these works should be performed by a dedicated editorial engineer.
11. 2. The editorial work includes:
preliminary study of the survey area using available materials and in situ, identification of characteristic features of the area that must be displayed on the maps being created;
ensuring timely collection and analysis of materials of cartographic significance, as well as determining methods for their use;
development of instructions in the form of an editorial note or editorial diagram for carrying out interpretation and surveying of the relief (including compiling samples), participation in the design of field interpretation routes and observation stations;
instructing performers on the content of these map sheets, the use of symbols, interpretation and depiction of relief;
participation in the management of work on field (ground, aerovisual) and desk interpretation of aerial photographs, relief drawing and compilation of original maps;
control over the quality of the specified work as it progresses;
organization of transcription of geographical names placed on topographic maps, as well as the names of geodetic points;
editorial review of completed interpretation materials and original topographic maps.
11.3. Before the start of field work and during it, the editor (or under his supervision) should identify, collect and use the following materials:
published topographic maps;
data from geodetic surveys of the area and reports on previously completed surveys;
departmental planning and cartographic materials: tablets of large-scale surveys, photographic plans with the results of agricultural interpretation, land plans of collective and state farms, forest management tablets, plans of forest plantations and schematic maps of forestry enterprises, plans of peat deposits, soil, geological and geomorphological maps, schematic maps of power and communication lines, longitudinal profiles of railway tracks, linear graphs of highways, navigation and pilot maps, diagrams of administrative boundaries and regional maps, magnetic declination maps, etc.;
various reference materials, including: directories of administrative-territorial divisions, tariff manuals and other directories on railway and waterways, directories of the hydrometeorological service, the Institute of Earth Magnetism, the peat fund, etc.;
lists of settlements indicating the number of houses, number of residents, presence of post offices, village councils, etc.;
tables of average annual changes in magnetic declination;
directions and data from water metering posts, extracts from passport data sheets of wells and springs, forest taxation descriptions, geological reports.
11.4. As a result of the analysis of materials of cartographic significance, the editor must give instructions on which materials should be directly used when deciphering and compiling original maps, and which ones should be used for general references. It is necessary to provide for checking the correctness of geographical names and those characteristics of objects that are transferred from departmental materials.
11.5. Editorial review of completed interpretation materials and field original maps is carried out after proofreading and acceptance by party leaders (foremen of the cameral part of the expedition). At the same time, the correctness of the depiction of terrain elements by existing conventional signs, the sufficiency of the characteristics of objects, the completeness and reliability of geographical names, the consistency of the image of contours and relief, the correct placement of inscriptions of elevation marks (including water edges) on the entire block of sheets are checked,
11.6. In the editorial note (diagram) compiled during stereotopographic and phototheodolite surveys, special attention should be paid to the depiction of the relief forms of the territory (in particular, hidden under the canopy of vegetation) and the nature of the distribution of microforms and their occurrence. Instructions should also be given on the use of additional and auxiliary contours, the set of elevation marks and the determination of various characteristics on stereo devices.
Attached to this note are samples of relief drawings, a diagram of linked marks of water edges (and along with the marks given in the low-water period, marks for the dates of flights should also be given), a diagram of the main road network, and if desk interpretation is expected using universal instruments - then decryption samples and a description of decryption features.
III. COMBINED SHOOTING
12. WORK PROCEDURE
12.1. Combined surveying is used primarily in flat-flat forested areas when creating maps at a scale of 1:10,000 with a relief section every 1 m. The technology of field work for combined surveying is presented in the diagram (Fig. 2 in adj. 1 ).
12.2. Aerial photography for the production of photographic plans is carried out using aerial cameras with a focal length of 140 or 100 mm on a scale of 1:40,000. The overlap of aerial photographs is set to 80´30% in order to cover each shooting trapezoid with one aerial photograph. In the latter case, the axes of aerial photography routes should be designed in the middle of the survey trapezoids.
12.3. Planned survey justification is carried out in accordance with the requirements of paragraph. 5.5 of this Instruction.
Work on the production of photo plans is carried out in accordance with the instructions of the current Instructions for photogrammetric work when creating topographic maps and plans.
Blueprints from photographic plans for field work must be made on semi-matte photographic paper glued to a sheet of aluminum.
12.4. To provide the high-altitude support necessary for surveying the relief, high-altitude survey networks are created by laying the main and survey high-altitude passages.
The main high-altitude passages are laid by technical leveling based on points of the main geodetic basis, the marks of which are determined by geometric leveling. The length of the main passage is allowed no more than 16 km, and the distances between the points of the passage should not exceed 400 m. The construction of passages with one or more nodal points is allowed. In this case, the length of moves between the source and nodal points is reduced by 25%, and between two nodal points - by 50%. In this case, the length of passages between strongholds can be increased by one and a half times.
12.5. Leveling is carried out from the middle. The excesses of the travel points are determined twice on the black and red sides of the slats, and there should be no discrepancies in the excesses; exceed 5 mm. Discrepancies in the passages are allowed no more than 0.20 m and are tied in proportion to the lengths of the sides. The move systems are equalized together.
Between adjacent trapezoids, 2-3 connection points are determined. The differences in the heights of communication points obtained from different main passages should not exceed 0.25 m. The points of leveling and main elevation passages laid along the frames of trapezoids simultaneously serve as communication points. Communication points should be noted in the field journal and on the elevation chart.
12.6. Surveying high-altitude passages are laid between the main high-altitude passages using the method of geometric leveling using a level or kipregel with a level on the pipe.
The length of passages should not exceed 6.5 km. Discrepancies are allowed no more than 25 cm in height and 1 mm in plan (on map scale). Height discrepancies less than 10 cm are not reconciled.
The positioning points of the instrument are located on well-identified contour points, and in their absence, the position of the standing points on the photoplan is determined by resections or measurements from the nearest contour points.
12.7. The relief is photographed on a photographic plane using a scale. The pickets required for shooting are selected within a range of up to 300 m at characteristic points of the relief, combining, if possible, with contours identifiable on the photographic map or defining them in a polar way. The heights of the pickets are determined from the points of surveying and main passages with a horizontal beam using kipregel with a level on the pipe. If necessary, excesses are also measured with an inclined beam at one position of the vertical angle (taking into account the zero point).
Additionally, you can select stations for terrain photography at contour points identified from the photoplan, transferring to them marks from at least two nearest points of high-altitude passages; The distances from the station to these points are measured with a rangefinder or using a photographic map.
In addition to the pickets necessary for depicting the relief, the elevation marks of the water edges in rivers and reservoirs and characteristic points of the situation and relief are determined in accordance with the requirements of paragraphs. 2.3 And 5.7 .
12.8. Horizontal lines are taken while at the survey station. If relief forms are not expressed by main horizontal lines, then they are depicted by semi-horizontals, auxiliary horizontal lines or corresponding conventional signs.
12.9. During the survey, a tracing paper of elevations is drawn up, on which all points of the geodetic basis, points of the main and survey passages, water edges, marks of characteristic points of the area and all other marks signed on the map are marked (see appendix. 8 ).
12.10. Interpretation during combined photography is carried out on photographic plans directly on the ground simultaneously with the terrain survey, while additional photography is carried out of the contours and objects of the terrain that are not depicted on aerial photographs or that arose after the aerial photography. Deciphering is carried out during work at the points where the instrument is located, and, if necessary, with an additional examination of the surrounding area. In addition to the photographic plan, the topographer must have a complete set of aerial photographs for stereoscopic viewing. Contours and symbols are drawn in pencil; in this case, instead of filling the contours with appropriate symbols, the use of abbreviated explanatory inscriptions is allowed.
12.11. In order to ensure quick production of copies from field originals, it is recommended that relief and contours be photographed on matte transparent non-deforming plastic, firmly fixed to the photoplane.
Drawing of survey results should be carried out in compliance with the requirements of the current symbols (but possibly with the use of decals). Drawing is carried out, as a rule, on the day of the field survey, leaving the edges in pencil until summaries are completed on the frames (except for free ones).
12.12. When surveying, the necessary characteristics of topographic objects are determined and geographical names are identified, and information about the area provided for by the installed program is collected.
12.13. Monitoring the accuracy of surveying on each trapezoid is carried out by laying control passages and a set of control pickets by inspecting persons.
The average differences between the heights of control points and their heights determined according to the plan should not exceed 1/3 of the accepted relief section.
12.14. Summary of field originals can be made by copying on wax a strip of the map 3 cm wide along the trapezoid frame (adj. 9 ) or using a measuring compass.
When summarizing, you need to ensure that the contour lines and contour lines match the frame, and check on adjacent sheets the consistency of the filling of the contours, marks of heights and water edges, characteristics of rivers, roads, explanatory inscriptions and names. Sharp bends of contours and horizontal lines along the frame line are not allowed, except when this is due to terrain features.
If there are discrepancies, they are eliminated by moving them; by half the value on each of the adjacent sheets, if these discrepancies do not exceed:
1.0 mm - for main contours (borders, railways, highways and improved dirt roads, streets of populated areas, coastlines of large rivers and canals);
2.0 mm - for other contours;
one and a half tolerances in the position of the contours specified in paragraph. 2.3 . of this Instruction.
If unacceptable discrepancies are detected, the head of the party is obliged to check the survey and establish the correct position of the contours and horizontal lines.
12.15. When performing reports with published maps of the same or larger scale, all corrections are made on the original of the new survey, if the discrepancies in the position of contours and contour lines do not exceed the established tolerances. If the discrepancies are greater than these tolerances, then corrections are not made, which is reported to the management of the enterprise.
In the event that a complete summary cannot be carried out due to the obsolescence of the adjacent map, it is permitted to leave a partial non-summary. In the card form you need to indicate what exactly remains unmixed, and make a corresponding entry in the margins of the original.
12.16. Upon completion of the summary, an inscription must be made in the margins of the original map indicating what the summary was made with (with the field original, circulation print, photocopy from the publisher’s original, etc.). For example: “Mixed with a field original on a scale of 1:10,000 from the 1974 survey, May 18, 1978. Topographer M.N. Sidorov.”
The correctness of the frame summaries inside the object being filmed is checked by the party leaders.
Free sides and frames on which reports were partially produced, as well as frames combined with published maps, must be checked and signed by the chief engineer of the expedition (if the survey was carried out using a combined method) or the head of the workshop if the survey was carried out using a stereotopographic method.
12.17. Editorial work during combined shooting is carried out according to the instructions in section 11 (pp. 11.1 - 11.5 ).
12.18. After the survey is completed, the original map, form, field journals, elevation tracings, copies of reports and a list of established names are handed in.
Annex 1
Rice. 1. Technological diagram of field work during stereotopographic survey
Rice. 2. Technological diagram of field work during combined survey
Appendix 2
Main characteristics of aerial cameras
Lens type | Focal Length(mm) | Field of view angle(degree) | Resolution (lin/mm) | Uncompensated radial distortion no more than (µm) | Shutter speed range, s |
||
Russar-Plasmat | |||||||
* Frame size 30´30 cm. Note. TE and TE-M aerial cameras are produced with shutters that provide a shutter speed range from 1/40 to 1/120 s or from 1/80 to 1/240 s. |
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Appendix 3
Shooting justification schemes
Rice. 3. Shooting on a scale of 1:10,000 with a relief section every 1.0 m
Rice. 4. Shooting on a scale of 1:10,000 with a relief section every 2.0 m
Rice. 5. Shooting on a scale of 1:10,000 with a relief section every 5.0 m
Rice. 6. Shooting at a scale of 1:25,000 with a relief section every 2.5 m
Rice. 7. Shooting on a scale of 1:25,000 with a relief section every 5.0 m
Rice. 8. Shooting on a scale of 1:25,000 with a relief section every 10.0 m
Rice. 9. Scheme of survey justification for the block
Rice. 10. Scheme of survey justification for the frame route
Appendix 4
Typical schemes for determining the coordinates of survey justification points
Method of triangulation constructions
Survey justification points can be determined from various triangulation constructions, the simplest of which is a triangle, the two vertices of which are combined with the triangulation points (Fig. 11 ). All angles in a triangle are measured.
The point to be determined can be located at the vertex of one of the corners of the quadrilateral, the vertices of the other two corners are triangulation points, and the vertex of the fourth corner is an auxiliary point (Fig. 12 ). Angles at a defined point (or at an auxiliary point) can be obtained as the addition of up to 180° to the sum of the measured angles of the triangle.
The determined point can be one of the points of the central system (Fig. 13 ). In one of the triangles of the central system, its two vertices must be triangulation points. All angles of the triangle must be measured.
Points are determined by inserting a system of triangles into a corner (Fig. 14 ). Angles at the midpoint (at the common vertex of the system) can be obtained by adding the sum of two measured angles to 180°.
The determined point can be included in a chain of triangles between two sides of the triangulation (Fig. 15 ) or between the side and the triangulation point (Fig. 16 ). All angles in triangles must be measured.
Corner serif method
Determining the coordinates of survey justification points using straight lines is carried out from at least three triangulation points or auxiliary points determined from triangulation constructions (Fig. 17 ).
Determination of the coordinates of points by resection is carried out using at least four triangulation points or points of triangulation constructions (Fig. 18 ).
The combined notching is performed according to the scheme shown in Fig. 19 .
A combination of resection at three geodetic points with measurement of true azimuth is allowed (Fig. 20 ).
Polar method
The polar method of determining the coordinates of survey justification points is to measure the direction and distance to the justification point from a triangulation point or an auxiliary point. The direction is determined by measuring at least two adjacent angles to adjacent points. The distance is measured with a rangefinder or tape, and is also determined by constructing a triangle with the side (base) measured. Measurements of angles and directions are carried out in two circular techniques, lines are measured twice.
Determining the coordinates of points using the polar method can be performed according to the schemes shown in Fig. 21 -27 .
The distance to the point is measured directly, and it is necessary to provide a control determination from the triangle by measuring its other side and two angles (see Fig. 21 ).
If, due to terrain conditions, it is impossible to construct a triangle, then from the determined point it is necessary to measure the directions to the nearest and two more visible points (see Fig. 22 ).
The distance to the point is determined from a triangle in which two sides and two angles are measured (see Fig. 23 ).
The distance to a point is determined from two adjacent triangles as an inaccessible distance (see Fig. 24 , 25 , 26 ).
If observations cannot be made at a triangulation point, then the point can be determined using a coordinate mapping scheme. In this case, at the point being determined (or at the auxiliary point), the angles between the directions to the nearest and two other triangulation points must be measured (see Fig. 27 ).
Combination of methods for determining coordinates
Various combinations of methods for determining the coordinates of survey justification points are allowed. In Fig. 28 shows the determination of points by direct intersection from triangulation points and from an auxiliary point.
In Fig. 29 An example of determining a group of points by resection using three triangulation points with control by an auxiliary point is presented. The coordinates of the auxiliary point are not determined in advance; By the convergence of the coordinates of the auxiliary point, one can judge the correctness of the measured directions.
In Fig. 30 shows a combination of serifs of different types. First, the auxiliary point is determined by a combined intersection, then the first justification point is determined by a resection using three triangulation points and an auxiliary point; the second point is determined by a straight line from the triangulation point, the auxiliary point and the first justification point.
A point can be determined by resection at three triangulation points and at another (or auxiliary) point, which in turn is determined by resection also at three triangulation points and at the first point (Fig. 31 ).
In Fig. 32 a diagram of an open theodolite traverse between two points is presented; in Fig. 33 - diagram of a closed polygon based on one point and in Fig. 34 - diagram of a system of theodolite passages with one nodal point.
Appendix 5
Fixing survey justification points on the ground
Points of planned and plan-altitude survey justification are fixed on the ground with long-term signs of type 1, 2, 3, 4, 5 (Fig. 35 ).
Type 1 sign is a concrete pillar with a cross-section of 12´12 cm and a height of 100 cm or a piece of asbestos-cement pipe of the same length and diameter, filled with cement mortar, placed in a pit or well to a depth of 80 cm. A metal nail with spherical cap.
Type 2 sign in the form of a pipe with a diameter of 40 mm with a concrete anchor is intended for laying in a pit to a depth of 50 cm.
Type 3 mark is intended for laying by drilling. Liquid concrete is poured into a well with a diameter of 15 cm and a depth of 80 cm to half the depth of the well, into which a piece of metal pipe with a diameter of 40 mm and a length of 100 cm is then inserted. The space between the pipe and the walls of the well is filled with compacted soil.
Type 4 sign is intended for laying in rocky soils. It represents a piece of metal pipe, the base of which is cemented into the rock.
Type 5 sign is intended for installation by drilling into permafrost soils and is a metal pipe with a diameter of 40 mm with a metal anchor with a diameter of 15 cm.
The external design of signs for long-term fixation on the ground consists of a ring ditch with a diameter of 1 m (along the center line) and a cross-section: 10 cm along the lower base, 30 cm along the top, 20 cm in height (for signs of type 1, 2, 3).
Types of signs for long-term fixation of survey justification points on the ground
A mound 20 cm high is made above the center. In areas of swamps and permafrost, the trench is replaced by a log house measuring 1´1 m, consisting of two crowns. On the side walls of the protruding part of a concrete pillar or pipe, the initial letters of the organization performing the work and the point number are inscribed with oil paint, for example GUGK, Vr.r.15.
To secure long-term signs, it is also advisable to use ledges of large stones, concrete foundations of power line supports, etc. The long-term point in this case is fixed by embedding a small metal rod, bolt or crutch in the cement mortar. Near the latter, an inscription is made in oil paint, consisting of the initial letters of the name of the organization performing the work and the point number.
It is prohibited to lay signs on arable lands and shifting swamps.
Appendix 6
Basic schemes of work during phototheodolite survey
Rice. 36. Layout of photographing bases:
a) on a narrow ridge; b) on a wide ridge; c) on a branched top; d) on a rounded top
Rice. 37. Schemes for determining the length of the photographing basis:
a) using an auxiliary basis; b) from an incomplete triangle
Rice. 38. Scheme for measuring control directions
Appendix 7
Palette for determining the working area of an aircraft radio rangefinder RDS
The working area of the aircraft radio rangefinder RDS is determined by the area between the circles limiting the maximum ranges D max and D min and angles j max And j min, plane notches from the base IN R radiogeodetic measurements given in table. 5 .
To build a palette, lay out the size of the base on transparent plastic or wax B R on the scale of the map (1:1,000,000) on which the work is designed. From the ends D And TO base draw circles with radii D min and D max (rice. 39 ).
Rice. 39. Palette of the working area of an aircraft radio rangefinder
Curves defining the positions of the vertices of the limit angles of the serifs j max And j min , are constructed by drawing circles from the centers " C" And "d" through the ends of the basis "TO" And "D". Position of centers "WITH" And "d" found at the intersections of the perpendicular "ab" to the middle of the basis with lines TO With And K d , drawn from the point TO at an angle j min to line "ab".
When designing works based on maps of a larger scale, when the palette sizes are large enough, an angle is constructed to construct a curve j min (or j max) on a wax sheet. Place the wax on the palette so that the sides of the corner pass through the ends of the base, and apply the apex point. By repeating this arrangement in different places, a number of points are pinned, and by connecting them the desired curve is obtained.
In Fig. 39 a palette is shown (halved) for designing radio geodetic work for topographic surveys on a scale of 1:10,000. The working area is shaded on one side.
Shooting instructions scale 1:5000, 1:2000, 1:1000 and 1:500" ...