Often distances on cards between, for example, settlements are not designated. At the same time on the traveling card there is a-degree scale on perimeter. Whether it is possible to define with its help necessary distances in kilometers and meters?
It is required to you
- - pocket calculator.
Instruction
1. Let's begin with the fact that from all linear measures existing in various countries to arc degrees, minutes and seconds of the earth's surface sea mile is most attached. She initially also thought thus. In fact, the nautical mile is one minute of an arch of a terrestrial meridian.
2. At introduction of the international linear measure – meter, it turned out that in their nautical mile 1852.4. Thus, it turns out that in one minute of an arch of a meridian on any card – whether sea, overland - one kilometer, eight hundred fifty two meters and forty centimeters. In one degree respectively: 1852.4 x 60 =111144 meter or 111 km, 144 m.
3. On sea charts the boatmasters determine the passable or remained way, distances to objects by the simplest measuring instrument. In the same way you can arrive, working with the map, say, of highways. For this purpose put needles of the measuring instrument in extreme points of the measured distance and then apply on a card frame to the ruler broken into degrees, minutes and seconds. Important for accuracy to take readings of distance on the same parallel. Because at transfer on the plane the meridians and parallels undergo natural distortions (Mercator projection). The closer to poles, the linear piece of minute, for example, will be longer. And if to measure the distance removed at more southern latitude on a-degree grid of the card above, indications in miles will be underestimated and vice versa.
4. Meaning that you, probably, operate with small distances, it is useful to know fullness of second of an arch of a meridian. This information is useful already and for pedestrian tourists, and even in everyday situations. One second as a result of again simple arithmetic calculations will make at you: 1852.4:60=30.87, that is about 31 meter.