AW: [Qgis-user] why is EPSG:2180 not recognised?

[Richard Duivenvoorde]

Jean-Claude Repetto wrote:

> Please read this thread on the PROJ.4 ML :
> <http://www.nabble.com/epsg-parameters-td16447986.html>
> 
> This is Frank Warmerdam's answer :
>  >
>  > The problem is that if EPSG offers more than one transformation to
>  > WGS84 for a datum, the automated translation gives up and offers none
>  > of them preferring for the user to make the decision themselves.
>  >
> 
> I think it would be better to create the srs.db database directly from 
> the EPSG database.

Hi Jean-Claude,
if I read that nabble-thread, my conclusion is: it's at this moment not 
possible to do a 1to1 translation for the EPSG-db to srs.db because of 
the simple fact that one epsg can have more set's of parameters which 
are 'valid/best' for different parts of the world.

I think there are some options though:

- add the definition YOU prefer for this specific epsg to your local 
srs.db in qgis (using for example sqliteadmin)

- it's also possible roll you're own projection for a qgis project isn't 
it? So you could make some 'template'-project in which you defined the 
projection with the exact parameters of you preference.

- incorporate ALL available definitions of these multi-paramter-EPSG's 
and add some interaction with the user to qgis in case there are more 
definitions available for one EPSG-code. And let the user choose from 
this list?

by the way: I will try to update the srs.db to match the ones used for 
proj (so only the ones where there is one set of parameters for one epsg)

Richard Duivenvoorde