National Geodesic Network and the transformation to SIRGAS - Chile, put into effect moving from the 2013.0 to the 2016.0 epochs for cartography and Geographic Information Systems

Abstract

The Military Geographic Institute (IGM) is the institution responsible for maintaining and updating the official geodesic reference framework of Chile, called the National Geodesic Network RGN SIRGAS-Chile. Due to the location upon the subduction zone of two tectonic plates, our country is unique in terms of the displacements and deformation of the planetary crust, having as its consequence, the deformation of the RGN over time. The above means that the coordinates calculated and adjusted for a particular epoch lose accuracy, with the result that the users of these coordinates also lose accuracy for their geographic projects and data bases. In response to this issue, the IGM should monitor these displacements and adjust to a new reference epoch, providing new coordinates to the vertices. In order to shift the information from one reference epoch to another, a conversion tool is needed that makes possible this change without it being distorted. In this way, the transformation parameters are calculated with Helmert methodologies, which are applicable in Geographic Information Systems in order to update the reference framework without damaging the information contained. This solution satisfies the requirements, mainly in the contexts of GIS and cartographic solutions, providing the solution required by the SDI of Chile.