For the correct determination of arrangement of objects on the card and calculations of distances it is necessary to know its scale. Usually on each card the linear or numerical scale is given, it is necessary only to read it. And here is how to be if for any of several reasons scale is absent? For its definition there are several ways.
It is required to you
- Topographic map, ruler
Instruction
1. Attentively consider the map and find a kilometer grid which has to be put down on it. The parties of squares of a grid correspond to a certain number of kilometers, you can recognize this quantity by signatures at the line exits stacks at edge of a frame of the card. For example, the distance between two neighboring lines of a grid is equal to 1 km. Measure this distance by a ruler. Let's say you received 2 cm. Thus, card scale: in 1 cm 500 m or 1:50000.
2. The second way of determination of scale – according to the nomenclature of the card. Attentively consider card details. The nomenclature represents the alphabetic and numerical name of a sheet of the map. Any large-scale row has the concrete designation by which the expert will easily determine card scale. For example, nomenclature designation M-35 designates scale 1:1000000; M-35-XI designates scale 1:200000; M-35-18-A-6-1 is scale 1:10000, etc. Certainly, for determination of scale in such a way it is necessary to have an idea of nomenclature designations and certain experience of the address with topographic maps.
3. The third way of determination of scale of the card – on the known distances. Find on the card of the image of kilometer columns on highways. Measure according to the card distance from one column to another. You learn card scale at once (the number of centimeters of the card will correspond to one kilometer of the area).
4. On cards of scale 1:200000 on roads distances between settlements in kilometers are designated. In that case measure according to the card by means of a ruler distance in centimeters from one settlement to another, and divide the signed number of kilometers into the distance expressed in centimeters. Thus, you received the card scale size, that is number of kilometers in one centimeter.
5. If you are on the area which is represented on the card, determine its scale by the measured distances. For this purpose measure distance between the plotted objects.
6. Use also knowledge of length of an arch of a meridian. One minute on a meridian is equal to about 2 km, and more precisely – 1.85 km. On side of a frame of the card signatures of degrees and minutes are given, every minute is allocated with a checker. If, let us assume, length of one minute is equal to 3.7 cm, then the scale of the card will be 1:50000 (one centimeter on the card is equal to 0.5 km on the area).