Reprojecting coordinates according to their geodetic datum
For a long time Darwin Core has a term to declare the exact geodetic datum used for the given coordinate. Quite a few data publishers in GBIF have used dwc:geodeticDatum for some time to publish the datum of their location coordinates. Until now GBIF has treated all coordinates as if they were in WGS84 , the widespread global standard datum used by the Global Positioning System (GPS). Accordingly locations given in a different datum, for example NAD27 or AGD66, were displaced on GBIF maps a little. This so called “datum shift” is not dramatic, but can be up to a few hundred metres depending on the location and datum. The Univeristy of Colorado has a nice visualization of the impact . At GBIF we interpret the geodeticDatum and reproject all coordinates as good as we can into the single datum WGS84. In order to do this there are two main steps that need to be done: parse and interpret the given verbatim geodetic datum and then do the actual transformation based on the known g...