Did you know that the oldest maps were peculiar topographic plans of the area, drawn with a sharp wand, feather, coal, ash, blood.
They later became the basis for mapping. In this article we will analyze what a terrain plan is.
Mapping Science
The science of mapping is called cartography. The history of this interesting field of knowledge dates back centuries. Maps were applied to a variety of surfaces:
- on the bones of large animals, for example, walruses or mammoths;
- papyrus;
- parchments;
- stones
- clay tablets;
- dishes and vases;
- paper.
Now everyone knows that a geographical map is an image of the surface of the earth on a plane in a reduced form. Let's take a closer look at it.
Topographic Plan
It was previously mentioned that primitive plans were the progenitors of modern maps. A component of any of them will have to answer a number of questions before depicting a terrain plan:
- What scale to apply?
- What shooting method to use?
- How to measure the azimuth?
- With which icons and pictures to depict objects located on the site?
Indeed, each such plan requires the use of special conventional signs, taken as a basis throughout the world. But first you need to decide on the scale, and then you need to choose a place from which the topographer will perfectly see the entire section, the plan of which is planned to be drawn. By the way, when constructing a terrain plan, the curvature of the earth's surface is not taken into account.
But did you know that to create modern terrain plans, a variety of specialized equipment is used: helicopters, airplanes, drones and satellites.
Polar survey of the area
For successful work in the cartographic direction, we advise you to study not only what a terrain plan is, but also to master different methods of shooting it.
For example, when conducting a polar survey, the north is first determined, after which a point is drawn, from which the survey itself is carried out (for this, the azimuth is determined and additional axes are plotted). Then, basic landmarks (monuments, pillars, corners and guides of houses, etc.) are drawn, and then the remaining azimuths (angles between the object and the north direction) are measured for each item displayed on the plan.
Objects mean all terrain elements depicted on the plan: buildings, fences, roads, poles, bridges, trees, bushes, flowerbeds, sports fields, rivers, lakes, hills, stops, parking.
Eye and route shooting
Eye tracking is the most affordable way. All measurements are carried out using simple devices.
A blank sheet of paper is attached to the tablet, and a compass is fixed in the upper corner. Referring to the device, spend the arrow from north to south. Then determine the azimuths of objects, which are indicated by conventional signs. At the final stage, all auxiliary lines are deleted.
With the route method of shooting, the whole path, taking into account all the turns, is divided into sections and the stop points from which the viewing area is applied to the tablet are selected.
Conditional signs of the plan of the district
Reading a map or plan without missing anything is not so easy. To best understand what a terrain plan is, you should study the conventions. And believe me, this is no more difficult than learning road signs.
Conventional signs of the plan of the area, as already mentioned, are special signs that are used to represent typical objects. They are the same for any region, for any corner of the world.
In topography, conventional signs are usually divided into the following types:
- Square or large. They transmit global, significant in area objects.
- Point or off-scale are used to apply churches, wells, significant monuments, bridges, factories and mineral deposits.
- Linear represent highways and railways, clearings, dirt, country, field and forest roads, streams, borders, power lines, horizontal.
- Explanatory notes are used to indicate additional characteristics, such as length, width, carrying capacity, nature of the road surface, thickness and height of trees, depth and nature of the soil.
So, we learned what a terrain plan is, and for its independent construction it is necessary to learn the following concepts: scale, azimuth, methods of shooting a plan and methods for measuring distances on the terrain (tape measure, measuring tape, field compasses).