[Qgis-developer] SRS DB maintenance

[Radim Blazek]

On Thu, Jul 4, 2013 at 11:36 AM, Werner Macho <werner.macho at gmail.com> wrote:
> Is it the same problem I had some years ago while doing some stuff on
> austrian coordinate system?
>
> I took a picture at that time how ESRI solved to manage it
>
> https://dl.dropboxusercontent.com/u/11824349/greenshot_2011-07-12_11-54-23.jpg
>
> If yes .. than cedric knows what I am talking about :)

Yes, we need something like that.

Radim

> regards
> Werner
>
> On Thu, Jul 4, 2013 at 11:30 AM, Radim Blazek <radim.blazek at gmail.com> wrote:
>> Note. The database from epsg.org does contain the correct
>> transformations (towgs84) 4836 (SK) and 5239 (CZ), the problem is that
>> each one is for a different territory but the same CRS. While the
>> relation between CRS and transformation in EPSG database is
>> (naturally) one-to-many, QGIS oversimplified the relation to
>> one-to-one. So all the evil comes from QGIS itself. We should probably
>> separate CRS from towgs84 and allow users to choose from multiple
>> towgs84 for CRS.
>>
>> Radim
>>
>> On Thu, Jul 4, 2013 at 11:00 AM, Radim Blazek <radim.blazek at gmail.com> wrote:
>>> On Thu, Jul 4, 2013 at 8:59 AM, Jürgen E. <jef at norbit.de> wrote:
>>>> 7805af3cf introduces a noupdate field in tbl_srs, that is set to 1 for the
>>>> mentioned CRSes.  And crssync doesn't update or delete records marked like
>>>> that.
>>>
>>> Great, thanks.
>>>
>>>> But that flag should probably tracked somehow and set to 0 eventually,
>>>> when the CRSes get corrected in/introduced to geotiff/GDAL/proj.4.
>>>
>>> It seems that GDAL is occasionally synced with EPSG from libgeotif
>>> [1], no additional overrides. In [2] is described EPSG in libgeotif.
>>> They keep overrides separate in gcs.override.csv and pcs.override.csv,
>>> it is not clear to me if gcs/pcs.override.csv are used somehow by
>>> crssync or not.
>>>
>>> If I got it,  If we want to get correct towgs84 params to srs.db in a
>>> clean way, they must be added to libgeotif gcs/pcs.override.csv and
>>> crssync must use them.
>>>
>>> BTW, we have a problem [2]:
>>>
>>> "Note that we deliberately keep alterations separate from the EPSG definitions
>>> in gcs.csv and pcs.csv to avoid violating the EPSG distribution license
>>> which requires that the definitions be distributed in unaltered form."
>>>
>>> Radim
>>>
>>> [1] http://trac.osgeo.org/gdal/log/trunk/gdal/data/pcs.csv
>>> [2] http://svn.osgeo.org/metacrs/geotiff/trunk/libgeotiff/csv/README
>>>
>>>>
>>>> Jürgen
>>>>
>>>> [1] http://en.wikipedia.org/wiki/DWIM
>>>>
>>>> --
>>>> Jürgen E. Fischer         norBIT GmbH               Tel. +49-4931-918175-31
>>>> Dipl.-Inf. (FH)           Rheinstraße 13            Fax. +49-4931-918175-50
>>>> Software Engineer         D-26506 Norden               http://www.norbit.de
>>>> committ(ed|ing) to QGIS                                IRC: jef on FreeNode
>>>>
>>>> --
>>>> norBIT Gesellschaft fuer Unternehmensberatung und Informationssysteme mbH
>>>> Rheinstrasse 13, 26506 Norden
>>>> GF: Jelto Buurman, HR: Amtsgericht Emden, HRB 5502
>>>>
>>>> _______________________________________________
>>>> Qgis-developer mailing list
>>>> Qgis-developer at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/qgis-developer
>> _______________________________________________
>> Qgis-developer mailing list
>> Qgis-developer at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/qgis-developer