[Qgis-user] ECW Projection

[Lee]

I had been trying to deal with this issue for a while, and just attempted
the above correction. What do you know, it worked. The projection showed up
on my map, with the correct location in it's CRS.

Where I'm continuing to have problems is when I set "on the fly
transformation" on. The image disappears, and I cannot zoom to its location.
It seems to give itself the Michigan Oblique Mercator SRS. My project is
either in WGS 84 or UTM Zone 17. Under WGS 84 it appears, but distorted and
in the wrong position. Under UTM Zone 17, it doesn't appear at all.

To avoid this, I attempted to warp the projection to a more useful CRS. The
following error was received:

gdalwarp -s_srs EPSG:3078 -t_srs EPSG:26917 WYANDOTTE_NE.ecw
WYANDOTTE_NE_UTM.ecw
ERROR 1: latitude or longitude exceeded limits
ERROR 1: Too many points (11881 out of 11881) failed to transform,
unable to compute output bounds.

I'm beginning to believe the CRS contained in the file is not correct, but I
was hoping for someone more experienced to make this judgment.
Thoughts?


On Wed, Jul 13, 2011 at 11:31 AM, <jonathanmoules at warwickshire.gov.uk>wrote:

> I can confirm my file has a .ecw.aux.xml
>
> If I remove the ".xml" from the file name it does work in qgis.
> Thanks
> Jonathan
>
>
> From:        Giovanni Manghi <giovanni.manghi at gmail.com>
> To:        jonathanmoules at warwickshire.gov.uk
> Cc:        qgis-user at lists.osgeo.org
> Date:        13/07/2011 16:15
>
> Subject:        Re: [Qgis-user] ECW Projection
> ------------------------------
>
>
>
>
> >         Just wondering if the project was aware of this as part of
> > their ongoing ECW issues, but when you load a geo-referenced ECW into
> > QGIS, it doesn't actually get properly referenced. Even if you
> > manually set the projection for both the layer and the project it
> > remains un-referenced with QGIS giving 0,0 co-ords to the top-left of
> > the image. This same ECW works fine in GvSIG, Kosmo, MapWindow and
> > ArcGIS. It's projected to EPSG: 27700.
>
>
>
> I was chatting a while ago with W. Macho and it was saying to me that it
> had a similar problem, with all his ECWs rasters to render on top of
> each other, as they don't had any referencing.
>
> A few tests and we find the issue. It depends on the extension of the
> file that (I guess) define the referencing. If the file is .aux then it
> si fine for gdal, if it is .aux.xml (if I recall correctly) it seems
> that gdal can't read the referencing.
>
> cheers
>
> -- Giovanni --
>
>
>
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-- 
all the best,
Lee
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