Many SRFs
There are a potentially infinite set of spatial reference frames based on the same Cartesian coordinate system with the same relationships to an ERM, but with differing ERMs.
- E.g., as defined by different ellipsoidal models
Or which may share a common ERM, but which have different relationships between the Cartesian coordinate system and the ERM.
- E.g., Geocentric (GC) and Local Tangent Plane (LTP)
Each of these spatial reference frames is unique, unambiguous, and can be exactly related to the others.
- And each has a customer-base for whom it is the preferred (only?) choice ...