ИСТИНА

For traditional maps we use regular reference surfaces as mathematical surfaces, for example, sphere, ellipsoid or triaxial ellipsoid and also various classes of projections. As the basis for development of projections of celestial bodies with irregular shapes the traditional cartographical projections have used. As the reference surface the regular surface of a sphere (being most simple for calculation) is used, and the altitudes of points on the irregular surface are measured from the reference surface towards normal. In this case, the points will have the same latitudes and longitudes as on a regular surface. The classification of traditional projections using a type of orthogonal cartographical grid is most convenient and simple. At this stage of development of irregularly-shaped celestial body’s projections it is possible to classify them as follows: - projections classified by shape of body, - projections classified by area of mapping region. By shape of body the projections subdivided into: - projections of celestial bodies with shape that is very different from sphere, ellipsoid, tri-axial ellipsoid – the bodies with shape like potato – “Potatographic projections”; - projections of celestial bodies with doubled shape; - projections of celestial bodies with polyhedral shape. By area of mapping region the projections subdivided into: - planetary scale projections; - projections allowing to map a body up to one hemisphere; - region scale projections