[postgis-users] Z and M coordinates seem inconsistent and barely supported

[Ben Harper]

I'm struggling to create a geometry field in PostGIS that stores Z and
M coordinates. Are these supported?
Some issues:
1. I cannot create a ZM field. "Dimensionality must be 3 or less"
2. GeomFromText() doesn't recognize "POINT Z (0 0 0)"
3. GeomFromText() does parse (with a warning) "POINTM (0 0 0)", but it
appears the DB isn't really storing the Z coordinate.
4. Using the C library interface, I can't get WKB geometry with Z to parse.

Thanks,
Ben