Symbols of the plan of the terrain. Topographic signs

Cartographic (topographical) conventional signs are symbolic background and dashed conventional symbols of various terrain objects that are used on topographic maps and plans. These signs are characterized by the commonality of designating homogeneous groups of objects. It is observed both in color and in shape. In this case, the main signs used in the compilation of topographic maps of different states do not differ much between themselves. As a rule, conventional signs convey the dimensions and shape, location, and also some quantitative and qualitative characteristics of objects, elements and contours of relief reproduced on maps. All of them are divided into area (large-scale), extra-scale, explanatory and linear. Briefly, we characterize each of these types.

Scale marks

Area, or scale, conventional symbols are used to represent those topographic objects that occupy a significant area. The sizes of these objects can be expressed in the scale of the plan or map. A conditional sign has two constituent parts. The first of these is the sign of the boundary of the object. The second is the conventional coloring or the signs that fill it. A dotted line depicts the outline of the object (bog, meadow, forest). A solid line shows the outline of a settlement, a reservoir. In addition, the contour of the object can be depicted with the help of the conventional sign of a particular boundary (hedge, ditch).

Fill Signs

The symbols for the plan of the terrain are diverse. One of their types is the filling signs, which are represented in a certain order inside the contour. The order can be arbitrary, chess. Filling signs can also be arranged in vertical or horizontal rows. Scale marks allow you not only to find the place where the object is located. Thanks to them you can also evaluate its outlines, area, linear dimensions.

Off-scale signs

This type is intended for the depiction of objects characterized by the length on the terrain. For example, this is the designation of a river, road or railroads, power lines, glades, borders, streams, etc.

Linear signs

They occupy an intermediate position, being between extra-scale and large-scale signs. The length of the corresponding objects is estimated from the scale of the map, but the width is outside of it. Usually it is greater than the width of the terrain object represented on the map, whose position corresponds to the longitudinal axis of one or another conventional sign. The horizontals are also represented by linear signs.

We have not yet listed all the designations of the plan of the area. We proceed to explanatory signs.

Explanatory signs

They are used to further characterize the items displayed on the map. For example, they denote the width, length and load capacity of the bridge, the nature and width of the road surface, the nature and depth of the ford, the average height and thickness of trees in the forest. Explanatory are the own names of objects, as well as various inscriptions on the maps. Each of these inscriptions is executed with letters having a certain size, and with the font installed.

The generalized sign

As the scale of topographic maps is reduced, homogeneous symbols of the terrain plan for convenience are combined into groups, which, in turn, add up to one generalized sign. The system of designations as a whole can be represented as a truncated pyramid. At its base are signs used for plans having a scale of 1: 500. Those that are used for maps with a scale of 1: 1 000 000 (they are called survey-topographic) are located on the top of this pyramid.

Colors

For all maps, the colors that have the plan area symbols are the same. It does not matter what scale they have. The dashed signs of structures, structures, lands and their contours, strong points, local objects, boundaries are executed in black. Brown is indicated by relief elements. Glaciers, streams, ponds and swamps on the map have a blue color (light blue - a mirror of water). Green is used when the forest symbol is represented. More precisely, it is used for tree-shrub vegetation in general. Light green serves to identify vineyards, shrubs, stlanniki, dwarf forests. Orange marked highway, as well as quarters, characterized by fire-resistant buildings. The yellow color is used to refer to improved dirt roads, as well as quarters, which include non-resistant buildings.

Abbreviations of names

For topographic maps, there are, in addition to conventional symbols, conditional abbreviations for the names of various political-administrative units. For example, the Moscow region is designated as Moscow. Also, abbreviations for explanatory terms have been established. The conventional designation of the swamp is bul., The power station is electric, and the south-west direction is SW. Using standardized fonts allows you to give important information in addition to conventional signs. For example, in fonts that are used for the names of settlements, their political-administrative significance, type, population is displayed. As for the rivers, you can get information about the possibility of navigation and their magnitude. The fonts used for the characteristics of wells and passes, elevations allow us to understand which of them should be considered the main ones.

Terrain

On topographical maps and plans, the terrain is depicted using the following methods: color plastics, washing, strokes, contours and marks. On maps of large scale, it is usually marked by the contour method, which has significant advantages over other methods.

Relative and absolute altitude

In order to correctly depict the relief of the surface of the earth on the plan, it is necessary to know what heights have points on it. On the ground there are lowlands, hills, mountains. How can you find out how low or high? To do this, you need to compare the heights of these objects with respect to any equal level. For the initial level take the surface of the sea or ocean.

Absolute altitude is the point of the earth's surface, which is reckoned from the level of the ocean or the sea. If the points are located above this level, then their height is considered positive (for example, the designation of the mountain top is a positive number). Otherwise it will be negative. The relative height is the difference in height from some point on the surface of the earth to the other.

How to set up conditional signs

All conditional topographical designations must necessarily have expressiveness, visibility. In addition, they should also be easily drawn. Symbols on the map, used for all scales, are established by instructive and normative documents. They are mandatory for all departments and organizations that carry out surveying work.

Land management organizations take into account the diversity of agricultural facilities and lands. It often goes beyond the accepted mandatory symbols. Therefore, land management organizations from time to time publish additional signs that reflect the specifics of agriculture. So there are new symbols on the map.

Map Generation

Local subjects, depending on the scale of the plans or maps are shown in different detail. For example, in a settlement on a plan with a scale of 1: 2000, only single houses of the same type will not be shown, and their shape will also be shown. But on a map with a scale of 1:50 000, there is an opportunity to present only blocks. What will happen if you increase it to 1: 1 000 000? In this case, the whole city will be represented by a small circle. The generalization of maps is a generalization of the elements of the relief, which is observed in the transition from the scale of the larger to the smaller.

Topographical designations, as you can see, are manifold. They help us to get information about the objects represented on the map. The designations of cities, villages, rivers and forests, etc., differ significantly from each other. No wonder, because they are completely different objects.

In conclusion, let's talk about such a concept as the plan of the terrain. It was met several times in this article and it may be incomprehensible to the reader.

Terrain plan

In order to farm and study nature, images of land surface areas are needed. The area with a small area can be photographed or painted. Usually the photo is taken from the earth's surface. Therefore, the near objects depicted on it, obscure the distant. Both the picture and the picture give us a certain idea of the terrain. However, they can not be seen on what form and size the site as a whole has. Objects that are placed on the surface will be better visible if the photo of the site is made from above, say from an airplane. An image obtained in this way is called an aerial photograph. The objects represented on it are similar to how they look on the ground. Their relative position and dimensions will be visible in this image.

The terrain plan also shows the top view. However, there are many differences between him and the photograph. The terrain plan is a drawing made on paper. It depicts a small section of the earth's surface in a reduced form. Plans differ from other images in that all objects represented on them are shown by conventional signs. There are many varieties of them. The simplest of them, which depict only individual objects, are called diagrams. The terrain map is a kind of topographic map.