[Gdal-dev] Merging DEMs seamlessly

[Frank Warmerdam]

Chris Pennock wrote:
> All - 
> 
> Merging DEMs is a frequent topic, but the suggestion I
> often see is like:
> 
> gdal_merge.py -o merged.tif dem1.dem dem2.dem
> 
> I when this is done, even if the two DEMs being merged
> have the *same* corner points, I usually get a few
> points of empty space between the dems in the merged
> tif. 
> 
> Does anyone have any thoughts on why this would
> happen, or a possbile fix? Perhaps the culprit is that
> neither of of two dems has the set of height points
> closest to the line forming their interface. I
> thought, however, that for every column of height
> points, that one dem or the other would have each
> point on the column. 
> 
> Many thanks in advance for this very newbie question!

Chris,

Can you provide a couple of DEM files which demonstrate this problem?
And what version of gdal_merge.py you are using?  There were some adjustments
made to try and address edge-effects some months ago.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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