A set of digital cartographic bases of the territory of Ukraine and neighboring countries. Scale range 1:12 000 000-1: 2500 000. Data format: ArcGIS (SHP), Adobe Portable Document Format (PDF) and Adobe Illustrator (AI)
Further in the text, consider the phrase "cartographic basis" equal in meaning "geographical basis". These two terms are used in parallel.
Cartographic bases are designed to display hydrological, synoptic and climatic phenomena within the territory of Ukraine. They can become the initial cartographic material for creating thematic atlases of various purposes, as well as for drawing up small-scale desktop thematic maps on the territory of Ukraine and its individual regions (several regions). In addition, a set of cartographic bases can be useful for displaying the results of scientific research, projects for fieldwork, and so on.
The initial source of cartographic data was the survey-topographic digital map of Ukraine OSM (Open Street Map).
The initial basis had topological and meaningful inaccuracies. For example, there was no r. Tisza (Carpathians). Some rivers have been digitized twice. Other linear objects (in particular, the same rivers) were torn, that is, they consisted of two separate lines with the same name in the attributes of the layer.
The detailed administrative areas and the borders of Ukraine did not coincide with the detailed water bodies along the coastline. The contours of some regions contained self-intersections (loops).
Inaccuracies can be attributed to empty space in the ranges of the Kiev region and Crimea on the site of administrative centers. In addition, some layers with similar content had different details.
To create the cartographic basis, the following software was used:
- the QGIS geographic information system - for editorial corrections and the re-digitization of some content elements, this GIS is free:
- open vector editor InkScape for stacking contours, their smoothing and preparation for publication of cartographic bases made in the geoinformation system; in the AI ??format, they can be converted by converting the PDF (Adobe Portable Document Format) file in which they are saved to the target format using the Adobe Illustrator program. To produce an interactive map or publish it on the Internet in Adobe Flash (*. SVF) format, the source vector files must be converted to the target format using the program of the same name.
The cartographic bases of various scales that are included in the set differ in content and in the detailing of the contours of the elements of content. The principle of visual georeference is based on the selection of these elements, that is, the presence or absence of certain rivers, lakes, roads or settlements. This means that the existing objects should be sufficient for geographic linkage of the represented phenomenon, that is, for understanding the geographic location of the contours of the thematic content of the map. On maps of different scale, a geographical phenomenon can be shown with different details, respectively, this detailing must be consistent with the detailing of the georeference. On the other hand, the elements of the cartographic basis should not prevent the mapping of the main content of the map,
The detailing of the content contours also depends on the scale. A set of cartographic foundations was created by generalizing the original framework and verifying its contents. As a result, the basis of the scale was 1: 2 500 000. It produced maps of smaller scales from 1: 3 000 000 to 1: 12 000 000. Each map of a smaller scale was made using a large previous one. This made it possible to avoid the appearance of elements that were not chosen for the target framework, on the basis of smaller scales. This approach simplified the generalization of contours - it was not necessary to check the consistency of their fragments, which did not change. At the same time, in case of greater generalization from a large base, the number of editorial revisions would increase in proportion to the scale of the map. Besides, After automatic generalization, the contours that overlap may be divergent in some areas. The reason for this is the dependence of the generalization algorithm on the direction of the contour. During the generalization of right-sided and left-handed contours, some disagreements arise. This means that the administrative boundaries of neighboring regions can have separate points with automated generalization, the position of which is different. These inaccuracies are identified during verification and are corrected manually. that the administrative boundaries of neighboring regions can have separate points under automated generalization, the position of which is different. These inaccuracies are identified during verification and are corrected manually. that the administrative boundaries of neighboring regions can have separate points under automated generalization, the position of which is different. These inaccuracies are identified during verification and are corrected manually.
Content elements are grouped by layers. This allows you to leave on the map only the necessary general geographic content, unnecessary layers can be disabled. Thus, cartographic bases can be used to create both analytical maps with one mapping index, and more complex integrated, synthetic and combined thematic maps.
Coherence of the bases in different formats. A set of cartographic bases is made in two formats: Shape and PDF. The mutual position (coordinate system) for the bases of the same scale coincide. This means that the thematic data applied to the map in the geographic information system can be transferred as a layer to a map in the vector graphics format without editing. But this is possible only if the original projection of the map is preserved in the GIS. To verify the correctness of the transfer, it is necessary to verify the location of any similar layers - they must completely coincide.
For a set of cartographic foundations, a direct conic equidistant projection was chosen, which is traditionally used for maps of individual regions, the European part of the USSR and Ukraine. It preserves lengths on all meridians and on one or two standard parallels. In particular, it is used by some cartographic enterprises in the atlases of Ukraine.
False_Easting = 0.0 - offset to the east;
False_Northing = 0.0 - offset to the north;
Central_Meridian = 31.5 - longitude of the central meridian;
Standard_Parallel_1 = 46 - latitude of the 1st standard parallel;
Standard_Parallel_2 = 51 is the latitude of the 2nd standard parallel;
Latitude_Of_Origin = 48,0 - latitude of origin;
Spheroid - WGS-84;
The unit of distance is a meter;
The scale factor is 1.0;
Geographical coordinate system: GCS_Ukraine_2000;
Angular Unit: Degree (0,0174532925199433);
Prime Meridian: Greenwich (0,0);
Semimajor Axis: 6,378,245.0;
Semiminor Axis: +6356863,018773047;
Inverse Flattening: 298.3;
Features of manufacturing.
1. Allocation of objects was carried out using the touchpad. The object selection (not by drawing the area) with a mouse manipulator could lead to object displacement, because some mice have poor balancing, for example Razer Naga, so the risk of displacement occurs every time a polygon is selected.
Since the original cartographic basis was obsolete, the geodata were updated from the satellite images of the geoportals.
On a cartographic basis of a scale of 1: 8,000,000, objects are shown and signed in such layers: regional centers, rivers, reservoirs, islands and braids. Showed, but not signed: the border of Ukraine, washing the border, washing the coastline, areas, rivers, canals, lakes, estuaries, islands and spits.
The position of all natural contours of a set of cartographic bases was verified by satellite imagery. To reduce inaccuracies, a large-scale foundation was converted into a projection of the image to reduce distortions of the latter. It also significantly accelerated the work, because transforming a snapshot from one projection to another requires considerable computer resources.
During the generalization of the contours, copies of the layers were used to estimate the extent of their changes.
Before each operation, the layer was saved under a new name. This made it possible, in the case of unsatisfactory results, to easily return to the previous version.
Several variants of making a set of cartographic bases were considered.
The first was to increase the detail of contours and objects of content. A map of the smallest scale from the set (1: 12,000,000) should have been made. For the production of large scale maps (1: 10,000,000 and 1: 8,000,000), new points must be added to the contours of linear and polygonal elements of content. In addition, new objects must be added. Thus, this manufacturing process was the most time consuming, almost all work was done manually. Therefore, he was rejected immediately.
Another technique provided a faster result, especially at the initial stage of the work. On it, the manufacture of foundations also began with a map of small scale. More precisely, the order of manufacture did not matter. But to ensure the smoothness of changing the detail of the cards should follow a sequence in their manufacture.
Each foundation must be designed individually. For all layers of objects, the selection qualification must be established by determining the maximum number of objects per unit area. To maintain the relative density of objects, which was supposed to transmit on the map their natural density, after selection for the qualification, a selection was made according to the norm. That is, a certain percentage of objects were deleted.
The contours of the selected objects should be generalized by establishing the maximum permissible detail. The latter was determined by establishing the minimum distance between the points. If the distance between two points of the contour was less than the minimum allowed, the second point was removed and the contour straightened. The minimum distance between the points was determined by the graphic accuracy of the map and the minimum curvature of the contours that could be transmitted on it.
After the generalization, verification was carried out and the inaccuracies found were eliminated. Such a technique made it possible to quickly produce the basics of small scales, but large-scale maps required a lot of effort. The disadvantage of the algorithm was a larger amount of work, which should be spent on multiple checking and correcting errors available in the initial basis. In addition, during the high degree of generalization, there was a possibility of significant and frequent differences in the contours that should have coincided (administrative boundaries, for example). In addition, there was a possibility of appearance on the map of small-scale objects that were absent in the previous basis. Therefore, this technique was also abandoned.
The most optimal would be to create from a data base the cartographic basis of a large scale, carry out editorial review, correct errors that have shifted from the original basis or have arisen due to generalization. And to make the basis of small scale, use the basis of the previous one.
Since the areas of the original base did not contain the areas of Kiev and Simferopol, these outlines were merged using the Merge function. The operation of combining contours does not make corresponding changes to the semantics of the object. Therefore, the latter was updated by recounting (the amount) of indicators in the Kiev region and the Autonomous Republic of Crimea.
Coordination of the shoreline of the Black and Azov Seas with the contours of the regions was carried out by generalizing the shoreline, updating it by satellite imagery and correcting topological errors at the seams of the coastline contours and the administrative area.
As the factors of generalization, the scale and purpose of the map were taken. Cartographic works for which similar bases were used were also studied. For example, in the National Atlas of Ukraine, the lines of the base are Bezier curves, which are not connected smoothly. This means that on the basis created in the GIS, the polylines have been transformed into splines. During the conversion to the vector editor format (to prepare for publication), the splines turned into Bezier curves.
Only natural contours are subject to smoothing. This procedure can be implemented both in QGIS, and in InkScape or in any vector editor.
On maps of scales from 1: 10,000,000 to 1: 3,000,000 cities are shown as punons. Necessities in the contours of cities do not exist.
The order of generalization. General geographic layers were generalized in the following order:
1) coastline - seas, limans. After the generalization, verification and updating were carried out;
2) the border of Ukraine and the borders of the regions; they are consistent with the coastline;
3) polygonal ponds - lakes, reservoirs, estuaries;
5) human settlements.
Certain objects are important, but do not appear on the map scale. They do not lend themselves to automatic generalization, since after completing the latter they have a too simplified form, which consists of three or four points. Such objects include: Zmeiny Island, Tuzla Spit.
To generalize the outlines, we used functions similar to the ArcInfo tools:
- Cartography Tools \ Generalization \ Simplify Line (Polygon) \ Bend Simplify;
- Cartography Tools \ Generalization \ Smooth Line.
- Cartography Tools \ Generalization \ Simplify Line (Polygon) \ Point Remove.
In calculating the generalization, we proceeded from the fact that the deviation of the line on the map of 0.1 mm is invisible. At a scale of 1: 8 million, this value is 800 meters. He was taken for the original. The QGIS tool removes unnecessary points, simplifying the line so that the deviation of the resultant from the original one is no more than the specified value. When comparing the generalized contour with the original, stored in another file, the maximum deviation between the contours did not exceed 734 m. The
maximum permissible displacement of the outline of the geographical base relative to its true position is 0.3 - 0.4 mm on the map scale. In this case, inaccuracies are not perceived visually and do not affect the readability of the map.
Some objects have been manually shifted to 1 millimeter in the map scale to improve the quality of the display of objects that are superimposed.
It is empirically determined that the number of points in the contour should be no more than 10 per millimeter of length. On sites with a small curvature, it is smaller. In the program Adobe Illustrator, if necessary, you can additionally smooth the outlines.
The minimum radius of curvature of a thin line on a map can be 0,4 mm, in the territory of a map with a scale of 1: 8,000,000 this value is 3200 m. The contours were generalized by removing sharp angles and reducing the number of points in broken lines.
The boundary layer of Ukraine contains a line that passes only overland territory, and also separates the Crimean peninsula from the Russian Federation. To ensure complete overlapping of the contours, the state border line was created by combining the polygons of regions into one polygon and turning it into a polyline. Part of this polyline on the offshore section has been removed.
Cities on the initial basis are represented by polygons. On maps of small scale, regional centers need to be given points (punchons). In addition, parts of cities on the basis of the basis consist of several polygons, especially if the first are located on rivers. To calculate the centroid, several neighboring parts of the city were combined into one object.
As the cities are usually shown on the rivers on which they stand, the corresponding punchons of cities were displaced perpendicularly to the contour of the river.
During the generalization of rivers, they should be left so much that they transmit the density of the river network and were placed more or less evenly. These 2 factors were accounted for by 50%. The generalization factor is the length of the river. Sewerage rivers are shown broken, for them the smoothing was not performed.
Since the coastline on the satellite image was significantly different from the existing polyline, the last one had to be digitized more than half. The northern and north-eastern part of the Crimean peninsula was completely redrawn. In connection with the significant difference in the outlines of inland water bodies and the location of the river beds with regard to space images, the generalization of the contours of these objects was carried out manually in parallel with the specification of the location.
During the generalization, the reservoir configuration was taken into account. If the pond is more or less rounded, it can be fed on the map with a line of appropriate thickness. If it is strongly stretched, the reservoir will look like a double line without a visible water mirror. Such reservoirs were removed. Also, parts of reservoirs with greater curvature were removed if the latter prevented their correct reflection. The characteristic features of reservoirs important for recognition (the configuration of the shoreline) were left. If these contours could not be expressed on a scale, they increased to the minimum acceptable level.
The alignment of the borders of Ukraine and regions was achieved by moving them to a single file for generalization. After the end of this process, the boundary line was transferred to a new layer.
The download of space images for updating was done using the SAS Planet program. The raster of the satellite images had the following coordinate system:
Linear Unit: Meter (1,0)
Preparing for publication provided for the conversion of the basis in PDF format and editing of the latter in a vector editor. All signatures have been re-located to achieve better consistency with the map's graphics.
The maps of the following scales were made, for each of them the length of the territory of Ukraine is indicated.
1:12 000000 - 11 cm; a quarter of the page;
1:10 000 000 - 13.2 cm; a quarter of the page;
1: 8000000 - 16.5 cm; half a page;
1: 6000000 - 22 cm; half a page;
1: 5,000,000 - 26.4 cm; one page;
1: 4,000,000 - 33 cm; one page;
1: 3000000 - 44 cm; to page rotation;
1: 2,500,000 - 52.8 cm; to page rotation;
In the agroclimatic atlas of the Ukrainian SSR, there are 20M basics, which are used as tie-cards to show an additional phenomenon.
Table 2 shows the density of points per millimeter of the curve length for generalization
For drying rivers, the thickness of the line is 0.254-0.317.
When making large-scale basics, it was decided to divide the rivers into signed and unsigned rivers and place them in different layers. For the basics of small scale, all the rivers are located in one layer.
The state border on cartographic bases is represented by a line, rather than a polygon. On the river sections, its passage coincides with the position of river beds. The border is shown also at the eastern coast of the peninsula of Crimea, the spit of Tuzla is highlighted.
The border washing was created in the GIS as a buffer zone. The color is 16.5% gray. Such values ??are associated with the requirements for offset printing. The thickness of the buffer zone for a map of scale 1: 8,000,000 is 2.5 mm. The thickness of the boundary line itself is 0.5 mm.
Washing of the shoreline is 10% gray.
Line of regions
During the preparation for printing a geographical base in a vector editor, the problem of superimposing the notation of the contours of regions was identified. Since the map actually identifies the polygons of the regions, and not their administrative borders. Accordingly, along the border of the regions, in fact, there are two lines from the polygons of neighboring regions. For a solid contour this does not matter. If you use dashed or dot-dashed lines, their graphic elements may overlap. In fact, this means that several different symbols of one object are used on the map.
Fig. 1. Different region sign