[Proj] Google maps of various flavors, and countries all overthe place.

Roger Oberholtzer roger at opq.se
Wed Oct 15 04:22:18 EDT 2008

On Tue, 2008-10-14 at 17:04 -0400, Frank Warmerdam wrote:
> Clifford J Mugnier wrote:
> > Isn't what is being proposed a duplication of the EPSG database?
> >  
> > What would such a "compilation" offer that EPSG does not?
> Cliff,
> I imagine it would contain suggested PROJ.4 strings for national
> coordinate systems (including some suggested towgs84 parameters
> for datums).  The PROJ.4 strings are not a duplication of EPSG,
> but it is true that the datum shift parameters might be.

That is it in a nutshell. It is fine to have a database that describes
the proper values for parameters according to some 'standard'. But
getting it into the EXACT form required for a specific country, in
practice, and verified against some reference data set, is what I seem
to miss. This includes command line, as well as C API parameter
specifications. And, where possible, verification data. This is what I
am suggesting.

Also, the parameters suggested in the EPSG database are often not the
only ones used in a country. I would suggest that the tracs discussion
allows variations on the official parameters to be discussed. For
example, one odd government department may do things different from the
norm. Such is the way of things.

Perhaps part of the process should be that the tracs pages may
occassionally indicate a need for a change, addition or clarification in
the EPSG database. It would be nice to have a place where the reasoning
for such an alteration is kept.


Roger Oberholtzer

OPQ Systems / Ramböll RST

Ramböll Sverige AB
Kapellgränd 7
P.O. Box 4205
SE-102 65 Stockholm, Sweden

Office: Int +46 8-615 60 20
Mobile: Int +46 70-815 1696

And remember:

It is RSofT and there is always something under construction. 
It is like talking about large city with all constructions finished. 
Not impossible, but very unlikely.

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