Abstract
The paper presents methods of area calculation, which may be applied for big
geodesic polygons on the ellipsoid. Proposal developed by the authors of this paper is
discussed. The proposed methods are compared with other, alternative methods of area
calculation of such polygons. Test calculations are performed for administrative units in
Poland. The obtained results are also compared with areas of those units registered in
statistical annals.
Utilisation of the equal-area map projections of the ellipsoid onto a plane seems to
be the best solution for the discussed task. In the case of small distances between points
we may expect accurate results of calculations, since the area size is influenced by the
projection reductions only, which are small in such cases. In some cases their influence on
results of calculations may be neglected. Then, only re-calculation of co-ordinates from the
GRS80 ellipsoid to the cartographic, equal-area projection is required.
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