[MetaCRS] 'FOSS Maintained' Source of CRS Definitions

[Howard Butler]

On May 12, 2008, at 2:52 PM, Norm Olsen wrote:
>
> OPERATIONAL APPLICATION
>
> Establishing an operational site sounds like a nightmare for a  
> volunteer based organization.  OGP/EPSG has established a web based  
> site from which a web client can obtain EPSG definitions in GML  
> form.  EPSG does not support all the definitions we would like.  So  
> I think the appropriate course of action is to establish a working  
> relationship with EPSG and use what they have established and work  
> to get the definitions we require added to the database.
>
> There may be fees involved in using this service, but funds to  
> operate need to come from someplace. :>)
>

At the time we rolled out http://spatialreference.org, the EPSG  
registry was just coming into existence (I don't know who preceded  
who, but EPSG's idea for the site must have existed for much longer  
than the two days in which we conceived and implemented sr.org ;).    
The EPSG registry website (http://www.epsg-registry.org) is atrocious  
to use, especially from a hands-off, developer perspective.  One thing  
we wanted sr.org to excel at was to allow softwares that can speak  
HTTP to easily be able to fetch (and create new) coordinate reference  
systems.  In that sense, I think sr.org has been a successful  
demonstration as shown by proj4js' and GDAL's ability to consume  
sr.org URLs and dereference them into something they can interpret. If  
we were to take on building something (as http://spatialreference.org  
or otherwise), I think that property of sr.org is an important one to  
keep.

I'll confess to being quite naive when it comes to coordinate  
reference system description, and I will gladly leave the details to  
the experts like yourself who work with this stuff all day everyday.   
On the other hand, I'm skeptical that coming up with a uber- 
encompassing dictionary of descriptions is a project that has a high  
probability of success.  A question I ask myself is if this problem is  
solvable, why hasn't it been solved yet?  Is it merely a communication  
problem, where getting all of the right people in a room can solve  
it?  Is it a complexity issue, where all of the permutations of how  
people/software can do things make capturing all of it a monumental  
task?  Is it a political issue, where organizations like EPSG who act  
as authorities move too slow to update their registry?  Does *THE  
STANDARD* already solve it and it is just generally not in wide enough  
use yet?

Is the juicy, solvable problem for MetaCRS the common description of  
coordinate reference systems (and all of the details that you've  
described), or is it software(s) that can speak all of the coordinate  
reference system description languages that are out there (31 flavors  
of WKT, proj, EPSG codes, etc) and act as a Babel Fish? Or, to be  
successful, do we really have to tackle both?

> OK, you can wake up now.  I'm done.

Thanks for the excellent treatise of where things are currently.   
Sorry that I just have more meandering questions to ask...

Howard