[Gdal-dev] projected bounding box

[Jonathan Coles]

hi,

I'm using gdal to project a geotiff image to be displayed underneath
vector map data. The extents that I use for the warping are the
projected coordinates of the window corners. Sometimes the image only
represents a small portion of the overall map and so the resulting image
that is generated contains lots of essentially useless data, but it can
take a very long time to render. To fix this problem I would like to
only render that portion of the image that is truly important by setting
the extents to the projected bounding box of the image's bounding box.
My problem is now this: how do I calculate an accurate projected
bounding box? I've found that simply projecting the corner coordinates
is not enough because sometimes the maximum extents are beyond the
corners, resulting in clipped images.

I was hoping that GDAL/PROJ would have a function for this, but I
couldn't find one. Any help will be much appreciated.

Thanks.

--jonathan

-- 
======================================================================
 Jonathan Coles                                jonathan at intevation.de
 Intevation GmbH                             http://www.intevation.de
======================================================================

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