Dear Matteo,
as you suggested off list, the solution is in this old thread:
http://n2.nabble.com/GRASSLIST-375-SRTM-coastline-sharpening-td1841248.html
i.e. you should probably use a newer version of the SRTM dataset, which is now at version 4. The website claims it to be the "highest quality SRTM dataset available":
http://srtm.csi.cgiar.org/
Kind regards,
Luigi
Date: Fri, 29 Jan 2010 16:13:58 +0100
From: "Matteo Toro" <ciccpaol@libero.it>
Subject: [GRASS-user] Coastline extraction
To: "grass-user" <grass-user@lists.osgeo.org>
Message-ID: <KX0KZA$5887F5E83EAD2C08A24FED403D3C6861@libero.it>
Content-Type: text/plain; charset=iso-8859-1Hi everybody,
I'm using an SRTM .tif file and a vector file (from vmap0 dataset) to clearly define a region.
On the srtm i filled the voids with r.fillnulls, but on the coast the data are no clear and coastlines are not real at all. The sea depth as well is completely "crazy", and I really don't need it!
Since i have got the vector file of the coastline, is there any way to tell grass to execute the command r.fillnulls just until the coastline?
I tried something converting at first the vector file of the coastline into a raster, and then i used the mask command, but I am not able to get the results that i need.
Many thanks!