4.7 CRS

Common has a CRS package, which has these abstract classes: AbstractProjectedCrs, AbstractVerticalCrs,and AbstractGeodeticCrs. Each of these classes has five concrete children:

• A projection identified by an EPSG code.
• A projection not known to the EPSG, which is defined using OGC’s Geographic Markup Language (GML).
• A projection that is intentionally obscured to anonymize a dataset. This is identified by a simple unvalidated string.
• A projection identified by a code according to a local authority. This would be used where a company or regulatory regime has chosen not to use EPSG codes.

• A projection identified by well-known text that complies with ISO 19162.