Scale shows how much the card reduces the real area which on it is represented. Only knowing this size, it is possible to lay off real distances on the map or the scheme of the area. It is possible to recognize scale by marking on the card. If that is not available, calculate it on lines of parallels.
It is required to you
- - various cards;
- - ruler;
- - calculator.
Instruction
1. If on the plan or the map the nomenclature of a leaf is put, then determine card scale by the special table. For example, if on the sheet of the map there is a marking of M-35-A, then its scale is 1:500000. It means that 1 cm on the card, on the area makes 500000 cm or 5 km.
2. If there is no marking, pay attention to a kilometer grid which is applied on any topographic map. The party of a square of such grid corresponds to the fixed number of kilometers. Measure by a ruler the party of this square in cm and find the distance relation on the card to real. It will also be scale. For example, if stack on the card of 4 km, and the distance between lines makes 2 cm, then scale will be equal to 2:4 km =2:400000 cm =1:200000 cm.
3. If the card of larger scale with parallels, then define it by this grid. For this purpose measure distance between two parallels put with a row in centimeters. On these nearby the standing parallels from bigger numerical value subtract smaller. As one degree of a parallel corresponds to 111 km, directly on the area, increase the received difference by this number and also number 100000 to transfer this distance to centimeters.
4. Find the attitude of the distance measured by a ruler towards result of calculations. Receive card scale. For example, if parallels go 0?, 10?, 20? etc. find a difference of two nearby lines. It will make 10. Then, increase this number by 111 and 100000. Receive 10•111•100000=111000000. If the distance measured by a ruler is equal to 4.5 cm, receive the scale of 4.5:111000000 cm? 1:25000000 cm. It means that one centimeter of the card 250 km of the area find room.
5. Measure scale on real distances. For this purpose lay off the known distance on the card, and correlate to real. For example, if the distance between two cities makes 400 km, and on the card it is equal to 8 cm, find a ratio of 8:400 km =8:40000000=1:5000000. It is also card scale.