[GRASS-user] r.proj's "use different location" error while working in different dbases

[Glynn Clements]

Nikos Alexandris wrote:

> Alternative solution with respect to the specific example here: allow
> g.copy to copy data from another dbase/location to the current dbase in
> a location with identical name and projection definition of course (?).

We don't currently have any way to check whether two projections are
identical, and this isn't a trivial question. E.g.:

1. Some of the parameters are floating-point values, so we would need
to choose some kind of tolerance.

2. Are WGS84 and NAD83 the same? In the absence of grid shift files,
the only difference is that the eccentricity of the WGS84 and GRS80
ellipsoids differ by 1.5e-6.

3. If the projections use grid shift files, do we just check that they
use the same file, or do we compare their contents?

-- 
Glynn Clements <glynn at gclements.plus.com>