Symbols of topographic maps - types and designations

Symbols of topographic maps - types and designations

Symbols of topographic maps provide complete information about the area. They are generally accepted and are used for topographic maps and plans. Topographic maps are important material not only for tourists, but also for geodetic organizations, for authorities that are engaged in planning the area and transferring the boundaries of sites.

Knowledge of conventional signs helps not only to read the map correctly, but also to draw up detailed plans of the area, taking into account the new objects that have appeared.

Topographic maps and plans

Topographic maps are a kind of geographic maps. They carry detailed information about the terrain plan, indicating the location of various technical and natural objects relative to each other.

Topographic maps vary in scope. All of them carry less or more detailed information about the area.

The scale of the map is indicated on the side or bottom of the map. It shows the ratio of sizes: indicated on the map to natural. Thus, the larger the denominator, the less detailed the material. Let's say a map 1:10 000 will have 100 meters in 1 centimeter. To find out the distance in meters between objects, using a ruler, the segment between two points is measured and multiplied by the second indicator.

  • The most detailed is the topographic plan of the area, its scale is 1: 5,000 inclusive. It does not count as a map and is not as accurate as it does not take into account the notion that the earth is round. This somewhat distorts its informativeness, nevertheless, the plan is indispensable when depicting cultural, household and economic objects. In addition, the plan can also show micro-objects that are difficult to find on the map (for example, vegetation and soils, the contours of which are too small to be depicted in other materials).
  • Topographic maps in scale 1:10 000 and 1:25 000 are considered the most detailed among the maps. They are used for household needs. They depict settlements, industrial and agricultural facilities, roads, hydrographic networks, swamps, fences, boundaries, etc. Such maps are most often used to obtain information about objects in an area that does not have significant forest cover. The objects of management are most reliably depicted in them.
  • Maps with a scale of 1: 50,000 and 1: 100,000 are less detailed. They schematically depict the outlines of forests and other large objects, the image of which does not require much detail. Such maps are useful for aeronautical navigation, road routes and so on.
  • Less detailed maps are used for military purposes to accomplish assigned planning tasks for various operations.
  • Maps with a scale of up to 1: 1,000,000 allow you to correctly assess the overall picture of the area.

Having decided on the task at hand, the choice of material seems to be absolutely not a difficult task. Depending on how much detailed information about the area is needed, the required map scale is also selected.

Scale of symbols

Symbols can be classified by scale (spatial extent of objects). So, they distinguish:

  • large-scale conventional symbols (areal and linear);
  • off-scale conventional symbols (dotted);
  • explanatory symbols.

At first glance, printed terrain maps have lost their relevance and are replaced by applications for smartphones and GPS-navigators. Electronic options are convenient, contribute to the rapid determination of their own location on the ground, but they have a number of significant drawbacks, one of which is unreliability. The ability to recognize the legend on a topographic map is necessary for orientation in unfamiliar terrain without electronic devices. Whatever modern navigator model you have, it will need regular connection to the mains or portable chargers to maintain stable performance. Also, navigation programs do not always correctly determine the location, which contributes to the lengthening of the route and complicates the process of reaching the destination. Paper charts do not need such careful maintenance and will always come to the rescue in conditions of survival. In the life of every person, situations arise when knowledge is needed about how conventional signs are deciphered on a topographic map. Thanks to the ability to determine them, you can easily go through any route, having only a printed circuit with you. In conditions of survival or getting lost, the presence of a terrain map in a backpack contributes to quick orientation and significant time savings. In the article we will consider what topographic maps are, their classification, conventional signs and correct decoding.

First, let's look at what a large-scale topographic plan of the area is (Figure 1).

Figure 1. Example of a topographic plan

By default, this is a universal scheme that provides as much information as possible about a specific area and acquaints the user with all the important details of the landscape: from the classification of plants and soil types to gas stations and railway crossings. The versatility lies in the fact that such a plan can be used for completely different purposes by travelers, motorists, surveyors, military, engineers, agents of construction companies, foresters, hunters, fishermen and many others without restrictions.

Certain prohibitions are imposed exclusively on objects of military importance.

Diagrams are created in the same way as online applications: by using images taken with the help of aircraft (recently, photographs taken by space orbiting satellites have been popular), after which they are translated into a plane and simplified.

This allows you to create the most accurate scaled-down landscape plan, on which the designations of the most important objects are subsequently applied. There are two main criteria by which the topography of the map should be created, conventional signs.

Criteria for creating a map:

  • Visibility. Since the topographic plan conveys all the details of the area visually, it should be as clear as possible for perception. The features of the relief, the presence of flora (less often fauna), railway and transport junctions, water bodies, large structures, settlements are clearly displayed;
  • Measurability. Since any terrain scheme has a scale, all designations can be measured with a ruler and a simple mathematical calculation can be made, according to which the length of, for example, a building or a forest belt is calculated.

Figure 2. Generalization example

How are topographic map symbols selected? This process is called generalization and includes the selective placement of icons that are of maximum importance to the reader (Figure 2). Unimportant buildings are not displayed in any way to save free space.

An algorithm for learning how to quickly read and translate the conventional symbols of geographic maps will be given below.

How to navigate the forest without a compass

Symbols history

Maps appeared when the human community arose, and with it the need to convey complex messages.

The first maps were schematic representations of hunting, fishing, routes, difficult or dangerous areas. In addition to stone, they used birch bark, flat animal bones (for example, a shovel), and clay tablets.

Symbols at first were drawings that conveyed individual characteristics, for example, instead of the name of a city on a map, they could depict the coat of arms of its ruler. Object outlines and distances were plotted approximately. A modern person (if he is not a specialist-historian) not only will not be able to “read” such a map, but will not even immediately understand that this is an image of some territory.

The most ancient (3800 BC) map of the northern part of Mesopotamia, dating back to the Akkadian period. On it you can find rivers, mountain ranges and cities, depicted, as now, in small circles. A way was required to visualize and record the number and relative position of settlements, fortresses, irrigation and other structures.

In Europe, the oldest map was carved on the "sun stone" (in Danish "solsten") about 5,000 years ago. its fragments were found during excavations on about. Bornholm in the Baltic Sea.

The oldest map on papyrus ("Turin Map", after the name of the museum where it is kept) depicts a small area of ​​a dry river bed (wadi), where gold was mined and stone was broken for construction. This map shows nearby villages and shows distances. It was made in 1160 BC. ... for an expedition organized by Ramses IV (New Kingdom).

The first map of the world, similar to the modern one, was drawn by Eratosthenes (3rd century BC), who headed the famous library in Alexandria. On his map there are already parallels and meridians passing through major cities. He was the first to determine the size of the Earth. His estimate of the length of the meridian on which Alexandria lies differs from the modern one by about 1%.

On the maps there were pictures of a mythological or biblical character and small texts.

In the Middle Ages, many natural science data were lost, and cartography fell into decay. Many of the legends are reminiscent of primitive maps. Only by the XI-XII centuries. Arab scientists re-collected information about the Earth and mapped it. In the XVIII century. technological breakthrough has allowed the creation of instruments for accurate measurement of heights.

This was the beginning of the development of cartography as a science, and then the unification of topographic symbols. On ancient maps, the object was often depicted in front, for example, the city was denoted by the battlements of the fortress wall and towers. This type has been preserved mainly in point marks. Modern symbols often show a general view of the object from above.

Designation of relief objects on the map

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