Raster SetBounds()

Frank Warmerdam warmerdam at pobox.com
Thu Oct 5 11:51:12 EDT 2006

Folks (especially Greg and Bob),

When I started the fdogdal provider I came to understand that it was
legitimate for an FdoIRaster to modify the passed in bounds in a
SetBounds() call.  I think one case Greg and I discussed was modifying the
bounds to match a pixel boundary.

Based on that I thought it was acceptable for me to "snap to image limits"
in the SetBounds() call.  That is, when an application calls SetBounds()
with a bounds that falls outside the bounds of the represented image, I
just trim the limits to the available image data.  I did this assuming
that the caller would be expected to call GetBounds() to learn the actual
detailed extents of the image that would be returned.

Last night I successfully tested fdogdal support in MapGuide (yipee!)
but I discovered that MapGuide is really expecting to get back the
area it asked for, which it does not when zoomed out such that part of
the map area is not covered by image.

Do I just need to buckle down and support any bounds in my provider?  Or
is this something that MapGuide is doing wrong?

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

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