[Gdal-dev] Merging Dems

[Joaquim Luis]

Chris,
If you can transform the dems into GMT grids than you can use grdblend. 
I never used it but from the manual
it does what you want.

Joaquim Luis

> 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.
>
>
>