[Qgis-user] Projection not recognised EPSG:31259

[Albin Blaschka]

Werner Macho wrote:
> Hi!
>
> You mean there's no rely to any .prj file i'll get anywhere?
> I mean - I understand that I should controll in every step i do if the
> results are ok or not .. but .. at least I thought (beside of
> controlling afterwards) that a projection should at least be recognised
> at what it is..
> And that seems not to be the case allthough it is definitely an EPSG
> 31259 ..
> So which program has a wrong database or where does this translation
> failure happen?
>
> regards
> Werner

Hello,

from Roland's (he was the person who brought first light for me in this 
issue) and my/our experience (we work together, sometimes ;-) the 
situation presents itself like that:

* If you have an ESRI-generated .prj-file, the towgs84 - parameter is 
missing: Programms using GDAL/Proj & Co. (like QGIS) need this parameter 
to be able to make projections on the fly. So, you have to edit the .prj 
file in question, or use the suitable one from the ones I sent earlier 
today, and name it accordingly  - if you make the jump from ESRI to QGIs 
for example

* If you stay just with ESRI, it is no problem, as far as I can tell, 
ArcGIS does projections on the fly within its programming logic, it 
seems (just a wild guess)

* As a conclusion: The .prj files are not really wrong, they are 
incomplete (Is there an official standard/definition somewhere?). To be 
on the safe side, make your .prj-files complete, because if ESRI 
stumbles over the towgs84-parameter it leaves it alone, so jumping back 
and forth is no problem...

* From a kind of "scientific" point of view: If you have the parameter 
in your .prj-files, it is documented what you intended to do with the 
data...

Maybe the situation is a little clearer now...

best wishes,

Albin


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| Albin Blaschka, Mag. rer.nat - Salzburg, Austria
| http://www.albinblaschka.info   http://www.thinkanimal.info
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