[mapserver-users] Projection issue with vrt file

[Frank Warmerdam]

On 12-04-20 06:39 PM, Morin, Marc-André wrote:
> Hi All,
>
> I'm trying to add a VRT raster file (BSB chart) to my mapfile, but it doesn't
> work totally.
> In fact, all of my tiles are generated, but they have no data... No error is
> logged...
>
> It sounds like the projection or the transformation matrix is not well
> supported, or not well configured.
>
> If I put in comments the GeoTransform element, some blank tiles are shown where
> the lower left corner is located at the origin (0.000, 0.000).
>
> Moreover, I successfully opened that same VRT file with QGIS, and the
> projection is ok...

Marc-Andre,

It is not clear to me why it is not working properly with mapserver, though
I would encourage you to define the projection of the layer's data in the
mapfile.  MapServer does not pull this from the underlying file by default.

I will also note that MapServer does not use the GCPs so you can ommit the
GCPList chunk from the VRT file.

If setting the PROJECTION block on the layer does not help, you can enable
debugging to get a better idea of what chunks are being selected from the
VRT file.

Best regards,
-- 
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