Obligatory condition of publication of any topographic maps or diagrams is an indication of scale, without which it loses its meaning and becomes just a beautiful overview picture. Usually the scale of the map is indicated in its description – the legend or brought into the surrounds. It can be specified as in the title, and together with the explanatory inscriptions at the bottom. Sometimes, a popular schematic maps of the scale of write right on the card itself. Look carefully at the map and find the inscription, "Scale 1:" or "M 1:".
If the map is cropped and surrounds, you can define the desired scale on the other map of the same area, the scale of which is known. Locate on both maps a pair of the same characteristic points of the terrain. This can be buildings or industrial facilities, junctions, characteristic features of the relief, which is reflected on that and on another map. Measure with a ruler the distance between them on both maps, and calculate the ratio between the scale – how many times the scale required is smaller or larger than specified for the other card.
Keep in mind that, usually, the scale is an integer that is a multiple of 100 or 1000 value. If you have a scale value is not, then this is due to the errors in the measurements, so bring a scale on your map to this value.
If the second card is not present, you will come to the aid of high technology. Use one of the mapping services available to Yahoo! or Google. They are based on transformed on a flat surface to space images, essentially card. Find the area that is depicted on your map with an unknown scale, and those two points that you chose as typical. Using the "Line" tool, determine the distance between these points on the satellite imagery in those units of measure that you select. Knowing the distance map and the distance on the ground, determine the scale of the map and cast it to an integer value multiple of 100 or 1000.
Advice 2: How to find the scale
The scale shows how many times the card reduces the real area that it depicts. Only by knowing this value, you can defer on the map or plan of the area real distance. To know the scale can be marked on the map. If not there, calculate it according to the lines of latitude.
You will need
- - various cards;
- - the range;
If the plan or map marked the item sheet, a special table to determine the scale of the map. For example, if a map sheet is labeled M-35-A, its scale is 1:500000. This means that 1 cm on the map, the terrain is 500000 cm or 5 km.
If mark does not exist, note the kilometer grid, which is applied to any topographic map. Side of the square of this grid corresponds to a fixed number of kilometers. Measure with a ruler the side of the square in inches and find the ratio of the distance on the map to real. This will be the scale. For example, if the stack on the map at 4 km and the distance between the lines is 2 cm, then the scale will be equal to 2:4 km=2:400000 cm=1:200000 see
If the map is larger scale with Parallels, then define it by using this grid. To do this, measure the distance between the two caused by a number of Parallels in inches. These adjacent Parallels from the larger numerical values subtract the lesser. Since one degree of parallel corresponds to 111 km, directly on the ground, multiply the difference by that number, and the number 100000 in order to convert this distance to centimeters.
Find the ratio of the measured range of distance to the calculation result. Get the scale of the map. For example, if Parallels are 0?, 10?, 20? etc. find the difference of two nearby lines. She will be 10. Then, multiply this number by 111 and 100000. Get 10•111•100000=111000000. If the distance measured by the ruler is equal to 4.5 cm, will receive a scale of 4.5:111000000 cm?1:25000000, see This means that one centimeter in the map fits 250 km area.
Measure the scale of real distances. For this known distance mark on the map, and correlate with the real. For example, if the distance between the two cities is 400 km, and on the map it is equal to 8 cm, find the ratio of 8:400 miles=8:40000000=1:5000000. This is the scale of the map.