The polar stereographic projection.

The projections are used for polar regions

Maps in the polar stereographic projection has the following properties:

1. meridians are represented by straight lines radiating from the pole at an angle equal to the difference in longitude ;

2. parallels are represented in the form of concentric circles , the distance between them increases with decreasing latitude , but more slowly than in the central polar projection ;

3. No distortion angles and poles in lengths slight distortion which increases with decreasing latitude slower than on the maps in the central polar projection. For example, at a latitude of 80 ° are less than 1 % and 75% of the breadth of at least 2 %;

4 . orthodromy slightly bent in the direction of the equator and at a distance of almost 1,000 km laid in a straight line;

5. loxodrome represents the curve and runs as well as maps and the conical projection.

On the maps plotted in stereographic projection conditional meridians parallel to the meridian of Greenwich (in red) and the meridian 90 ° East (blue). In this projection, published flight and on-board maps of the Arctic and Antarctic scale 1: 2 000 000 1 3 000 000 and 1:4 000 000. Some of the cards of the polar stereographic projection is constructed so that the picture plane whips globe on the parallel 70 °. On such cards distortion lengths near the parallel 70 ° minor.

To account for the distortion of the lengths on the map along one of the meridians and along the sides of the internal framework of the distance scale printed on a variable scale of the pole and from longitudes 0 ° and 90 ° or 90 ° and 180 °. Measurement with these scales is as follows. Measured portion carried on one of the scales which is closer towards this portion. Transfer is performed in such a way that the middle point along its portion moved parallel. Then take a reading on the scale of distances corresponding to the extreme points of the measured section, and their difference is taken to be equal to the required length.

Map - reduced constructed by mathematical laws , the image of large areas of the earth's surface or the entire earth's surface on a plane.

It is with the help of a map can be identified on the Earth's surface , that is, to know their place , why - the control path , and , if necessary, to determine the future direction of flight.

With all the amazing variety of existing maps, most of them share some common features. Even the contour maps , the maximum unloaded in order to help students to apply to them additional information of their choice, usually have

- Marginalia (font) registration card - the title ;

- Coordinate (degree) grid coordinates - orienteering maps in relation to the cardinal points , scale,

- Signs and symbols , and accompanied by a legend .

- Elements of the framework (eg , coastlines ) .

- Special load - depending on the purpose of the map

Aeronautical charts are meant for planning the preparation and implementation of aviation. Map projection of these maps, content and design are subject to the satisfaction of the requirements of air navigation.

Map content (load ) - the degree of the topographic terrain elements on it , and other information necessary for practical purposes ( for the intended purpose of this type of card ) - API . The completeness of the display depends on the scale of the map. The bigger the map , the more information it contains . In drawing up the maps, which is applied to only those elements of the terrain and specific information that is required when using the data card.