[Qgis-developer] usability enhancements for georeferencer plugin

Hugentobler Marco marco.hugentobler at karto.baug.ethz.ch
Wed Oct 31 01:48:16 EDT 2007

-----Ursprüngliche Nachricht-----
Von: Oleg Gusev [mailto:oleg at crista.uni-wuppertal.de]
Gesendet: Di 30.10.2007 11:35
An: Hugentobler  Marco
Cc: qgis-developer at lists.qgis.org
Betreff: Re: AW: [Qgis-developer] usability enhancements for georeferencer plugin
Am Dienstag 30 Oktober 2007 10:54:40 schrieben Sie:
>> It is not clear to me what you mean with 'CRS of the referenced image'.
>> Isn't that unknown in the normal case? After referencing, the image has the
>> CRS of the control points.

> you are right, but such general approach may have bad side effects.
> If the referenced images are in a local metric coordinate system
> (for example transverse mercator) and the GCPs are longlat WGS84
> taken from GPS, then one usually don't want to create the georeferenced
> longlat WGS84 raster. At our latitudes it leads to a 1:2 pixel distortion.

Ok, I see. So the user should have the possibility to specify source CRS of control points and target CRS of control points (which would then be the CRS of the referenced image). I think that can be done quite quickly. I'm going to make an enhancement entry in the bugtracker for this.


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