In the previous articles we provided an introduction to coordinate systems, geoids, datums and projections. This background information was needed in order to delve into more details on transformations and changing projections in the various software packages to help you do more with LIDAR data. This article will provide the information into transformations and changing projections within LP360, GeoCue and Terrasolid.
Changing Coordinate Systems
It becomes necessary, at times, to change the coordinate system assigned to LIDAR data for a final delivery of the data. For instance, the LIDAR data may have been processed using the horizontal coordinate system NAD83 UTM 19N meters and vertical coordinate system of Ellipsoid meters. However, as part of the final delivery the LIDAR data needs to be put into horizontal coordinate system NAD83(2011) State Plane Maine West Feet and vertical coordinate system of NAVD88 Geoid 12A Feet.
In order for the data to be projected from one coordinate system to another, in the above example, a transformation needs to take place. The transformation that is defined will determine how the data is translated to the new coordinate system. The accuracy of the transformation can range anywhere between a couple of centimeters to a few meters dependent upon the transformation method and parameters that are chosen.