Geodesic vertices

Digital base containing the network of geodesic vertices that covers the Andalusian territory. The Spanish Geodesic Network was started in 1852 by the Commission of the Map of Spain, being constituted by three orders of triangles according to the dimension of their sides (networks of first, second and third order). Its construction and total observation took almost a century, and geodesic works could be considered completed in the 1930s of the present century. The purposes of establishing the network can be summarised as follows: Implementation throughout the Spanish territory of a 3-dimensional Geodesic Network of Zero Order, with a high precision similar to that achieved by the fiducial stations of ETRF-89, that is, in the centimetric order; determination of precise processing parameters between ETRF-89 and the European Datum 1950 (ED50); finally, make it easier for GPS users to merge their space observations with conventional ones and provide a dense network from which accurate real-time corrections (DGPS techniques) can be obtained useful for navigation. (José Antonio Canas. Magazine Sources Statistics. Statistics and Geography — Magazine No. 38 — October 1999)