This allows one to select either a map projection or geographic system from the EPSG database of systems that is supplied with OpenSpirit. You can narrow the list of choices by specifying a portion of the system name and/or selecting a point on a map to get systems appropriate for this location. After selecting a system, if it is based on a datum other than WGS84 you must also select an appropriate datum shift (geographic transform). In order to see the parameter values implied by a chosen system or transform simply click on the "Details" button.