engleski

Perspective Projection of the Earth and the Hidden Lines

The paper deals with the general perspective projection of the earth's sphere in which the points are mapped onto the plane according to the laws of the linear perspective. The need arises to classify such mapping into external and internal ones, and to subdivide each group into those with positive, and those with negative presentation. Namely, a circle on the sphere exists which decomposes it into two parts, which are mapped in different ways regarding the kind of mirroring needed in order to obtain the usual distribution of the cartographic elements on the final map. The proposed derivation is easy and concise, and the resulting equations have much simpler form than it is usual. In the computer-aided graphical presentation for cartographic purposes only a part of the earth's sphere should be considered as visible.Therefore, the paper offers appropriate algorithms in order to draw only visible part of the graticule, as well as, other line elements (e.g. continents outlines).

linear perspective ; general perspective projection ; external perspective projection ; internal perspective projection ; hidden lines

The full text is available at ResearchGate https://www.researchgate.net/profile/Nedjeljko-Francula