Necesidad del geoide en el posicionamiento con GPS

Resumen

The common use of global positioning systems, and specially GPS, in work like survey, cartography, photogrammmetry, LIDAR... make it necessary have a gemid model to transform ellipsoidal to orthometric heights used in engineering. Because of the lack of parallelism between both reference systems not to have these models can produce important errors since the variation can take values of 10cm/Km or more in some areas, for example in the SW of Spain. If we do not consider this difference in the elaboration of DTM used to design substructure can happen that in gravity canalization the water does not arrive at the wanted point