[Gdal-dev] (no subject)

[Chris Pennock]

Hi all,

Merging dems seems like a common task, but I
cannot find a way to do it well using gdal. Is there a
best practice I should be aware of?

I realize that there will always be gaps between dems,
which must be fixed afterward (thanks Craig and Ben),
but what is the best way to merge the dems together,
with "clean" NODATA edges, so that the gaps can
be filled?

The problem I run into is that warping with "-rcs" for
cubic spline resampling, which looks best, leaves the
edges of the dem "rounded off". E.g. if the data
should be:

1000, 1000, 1000, NODATA, NODATA

I get instead:

1000, 1000, -400, -5000, NODATA

And so I don't have clean cut offs from data to
NODATA, which makes gap filling challenging.



Any help would be much appreciated.

Thanks,
Chris

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