Creating a Coordinate System from Scratch

  1. Open Map Projection Settings Main: Project > Settings > Set Map Projection
  2. Select a project reference datum from the Datum tab and select the Custom Coordinate System.
  3. On the Elipsoid tab, select the desired ellipsoid. Make sure the projection and associated ellipsoid match the chosen Reference Datum.
  1. On the Projection tab, select the specific projection type and projection parameters such as central meridian.  Petra will accept LatLon values in either decimal degrees or as degrees:minutes:seconds.

The parameters listed will depend on the specific projection type.  As an example, only the UTM projection lists UTM zones.

  1. Click,Save to enact the changes.  
For new projects this will simply set the project's map projection.   For existing projects, saving a different coordinate system means that the XYs of all the data will need to change as well.  Make sure to
  1. Select Yes when asked to recompute XY well locations using the new map projection.