The terrain plan is ... What's the difference between plans and maps?

The second language of geography is a cartographic image. Maps were used even by ancient navigators. When planning the expedition, the researchers collected all available cartographic materials for the required area. Upon completion, the results were transferred to paper. So the plan of the terrain was created. This was the basis for creating new maps. What is the plan of the terrain and what are its fundamental differences from the geographical map?

What is the terrain plan ?

The very first maps in the history of mankind were plans. Now they are used practically in all branches of science and technology: without them, construction, agriculture, engineering research, etc. are not enough.

The terrain plan is an image of a large scale of a part of the earth's surface, with the use of conventional signs. As a rule, cartographic images for small areas with areas up to several square kilometers are compiled. At the same time, the curvature of the earth's surface does not affect the image in any way.

How is the plan different from the map?

Often in life we meet both the map and the plan of the terrain. Geography as a science relies on these cartographic images. But this is not the same thing.

When creating a geographic map, a smaller scale is used (that is, a larger area is covered), the nature of the earth's surface is taken into account, that is, the mathematical law of the image-projection is used. The most important element of geographical maps is a degree grid: it is necessary for determining the sides of the world. Parallels and meridians are often represented by arcs, not straight lines. Only significant large objects can be put on the map. For their compilation, a variety of materials are used, including maps of a larger scale, space images.

The terrain plan is a more detailed image of a small section of the Earth. It is constructed without taking into account the projection, since by virtue of the size of the section the surface is assumed to be flat. The sides of the world are defined by the directions of the plan's framework. Absolutely all terrain elements are displayed. They are based on materials of large-scale aerial photography or on the ground.

How is the plan drawn up?

To start, a point is selected in the area from which the whole area to be mapped is clearly visible. After this, it is necessary to choose the scale of the future plan. The next step is to determine the direction to the north. You can do this with a plank and a hand-held compass. On paper, you need to identify the point from which the survey will be conducted, and then draw all the main landmarks (corners of buildings, large trees, pillars).

Then, with the aid of special high-precision instruments, the azimuths are measured to each point, which must be reflected on the plan. Each time azimuths are deposited from the main point and an auxiliary line is drawn from it, an angle is marked on the plan. The distance from the main to the sought-for points of the terrain is also measured and transferred to paper.

Then, in the conventional symbols, the site objects are displayed, the necessary signatures are made.

Scope of the terrain plan

Throughout the area of the cartographic image of the plan, its scale remains unchanged. The scale is of three types:

• Numerical.
• Named.
• Linear.

The numeral is expressed as a fraction whose numerator is 1, and the denominator is M. This number M indicates the degree of reduction in image dimensions on the plan. Topographic plans have scales of 1: 500, 1: 1000, 1: 2000, 1: 5000. For land management works also smaller scales of plans are used - 1:10 000, 1:25 000, 1:50 000. The scale is considered to be smaller, which has more M, and vice versa.

With a named scale is simpler - here the length of the lines is expressed verbally. For example, in 1 cm - 50 meters. This means that 1 cm of distance on the plan corresponds to 50 m in the terrain.

The scale of a linear type is a graph depicted as a straight line segment that is divided into equal parts. Each such part is signed by a numerical value of a commensurate length of the terrain.

Symbols of the plan of the locality

In order to display any objects or processes on the topographical plan, to indicate their important qualitative or quantitative values, it is necessary to use conventional signs or notations. They give a complete picture of the spatial arrangement of objects, as well as their characteristics and appearance.

There are four types of conventional symbols:

• Large-scale - linear and area (for example, the areas of states, roads, bridges).
• Large-scale (well, spring, pillar, tower, etc.).
• Explanatory (signatures of characteristics of objects, for example width of highway, names of subjects).

In the legend of the plan, they are all reflected. Based on the legend, a primary view of the site is drawn up.

So, the terrain plan is a cartographic image of a small section of the earth's surface on a large scale. It is used in almost all spheres of human activity. Without it, it would be impossible to create topographic maps.