Coordinate Reference Systems (CRS)

Coordinate Reference Systems describe location in a standardized form. Depending on the data collected, different CRS can be used. It is important to find a common CRS, when different data layers need to be combined, to ensure alignment with each other. The former European Petroleum Survey Group designed structured datasets of CRS and Coordinate Transformations and referenced them with EPSG codes. For example, Google Earth uses Latitude/Longitude (WGS84) referenced by ESPG:4326 and most map tiles use mercator projection referenced by EPSG:3857 A more comprehensive overview can be found at: https://www.nceas.ucsb.edu/~frazier/RSpatialGuides/OverviewCoordinateReferenceSystems.pdf