ABSTRACT
People live on Earth and learn to cope with its terrain. Civil engineers design and construct buildings on it; geologists try to study its underlying construction; geomorphologists are interested in its shape and the processes by which the landscape was formed; and topographic scientists are concerned with measuring and describing its surface and presenting it in different ways, for example, using maps, orthoimages, perspective views, etc. Despite these differences in emphasis and interest, these specialists have a common interest, that is, they wish the surface of the terrain to be represented conveniently and with a certain accuracy.
