Incomplete extent of raster after reprojection - corner missing

[Frank Warmerdam]

On 10/30/05, Delfos, Jacob <jacob.delfos at maunsell.com> wrote:
>
>
> Hi List,
>
> I have a raster which I am reprojecting on the fly from LCC to either UTM or
> Latlong. I just realised that in each mapimage, it misses a small corner at
> the bottom-right. The background colour of the map shows through. It appears
> that the slice being cut out of the raster-image prior to reprojection is
> too small; after reprojection, the cut-out slice doesn't cover the map-image
> completely, because of the distortion due to reprojection. This problem
> occurs every time the layer is drawn.
>
> I have attached part of the map-image. The background of the map is light
> yellow, as is the bottom-right of the image. The height of the corner
> missing is typically about 8% (compared to mapimage-height). It occurs in
> php_mapscript version 4.4 and 4.6, using gdal 1.26 and 1.31 respectively.
> The raster is an ecw.
>
> It's no major drama, but I was hoping it might be easy to fix…..

Jacob,

I'm not sure why this is happening, it is not a common behavior.
If you can boil this down to a simple mapfile, and raster dataset
that can demonstrate this problem with a particular shp2img
call then I would encourage you to submit it in bugzilla, and
assign it to me.

Normally mapserver does a variety of sampling along the request
edges in an effort to get all the data needed.  The only obvious
reasons I could see for such a failure is if the projection transformation
is failing for that corner.

Best regards,
--
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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and watch the world go round - Rush    | Geospatial Programmer for Rent