Well, you assuming that NULL=0, but the sole reason for having NULL layer in grass is that those values are not identical.
Boris On Nov 16, 2007 5:55 PM, Charles Ehlschlaeger <[EMAIL PROTECTED]> wrote: > > I couldn't figure out how to make gdal_merge output NULLs > > instead of 0s (and what formats support NULLs?). > > r.mapcalc can easily convert your 0s into NULLS with the expression: > > newmap = if(map == 0, null(), map) > > r.mapcalc will solve most raster problems. GRASS users are advised to know > that program inside and out. > > Sincerely, chuck > > Chuck Ehlschlaeger, Associate Professor of Geography > Western Illinois University > 215 Tillman Hall, 1 University Circle, Macomb, IL 61455 > [EMAIL PROTECTED], phone: 309-298-1841, fax: 309-298-3003 > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Boris Avdeev > Sent: Friday, November 16, 2007 1:11 PM > To: [EMAIL PROTECTED] > Cc: [email protected] > Subject: Re: [GRASS-user] r.patch for stitching rasters? > > Yes, though I couldn't figure out how to make gdal_merge output NULLs > instead of 0s (and what formats support NULLs?). > But anyway, you think that this is normal performance? > > On Nov 16, 2007 2:08 PM, Dylan Beaudette <[EMAIL PROTECTED]> wrote: > > On Friday 16 November 2007, Boris Avdeev wrote: > > > > > Now, when you asking... > > > Now it is this: > > > > > > projection: 3 (Latitude-Longitude) > > > zone: 0 > > > datum: wgs84 > > > ellipsoid: wgs84 > > > north: 48:50:24.701676N > > > south: 34:38:56.353164N > > > west: 45:57:00.735336E > > > east: 55:00:56.276712E > > > nsres: 0:01:00.033312 > > > ewres: 0:00:59.991804 > > > rows: 851 > > > cols: 544 > > > cells: 462944 > > > > > > But I believe that at the time I started r.patch it was this: > > > > > > projection: 3 (Latitude-Longitude) > > > zone: 0 > > > datum: wgs84 > > > ellipsoid: wgs84 > > > north: 46N > > > south: 35N > > > west: 35E > > > east: 55E > > > nsres: 0:00:03 > > > ewres: 0:00:03 > > > rows: 13200 > > > cols: 24000 > > > cells: 316800000 > > > > > > since I was trying to preserve resolution of original srtms. > > > > > > Boris > > > > > > > That is pretty big, but not impossibly big. Have you considered something > like > > gdal_merge.py for merging the files outside of GRASS ? > > > > cheers, > > > > Dylan > > > > > > > > > > PS Sorry Dylan > > > > > > On Nov 16, 2007 12:49 PM, Dylan Beaudette <[EMAIL PROTECTED]> > wrote: > > > > On Friday 16 November 2007, Boris Avdeev wrote: > > > > > Hello grass (ab)users! > > > > > I am using r.patch to merge 200 1 degree, 3 seconds resolution > srtm's > > > > > (1-2 Mb each). After 24 hours of real time and 20 hours of Xeon > > > > > processor time I have 39% completed! My guess that this task > shouldn't > > > > > take so long. Is r.patch a wrong tool to do this thing? Or is it a > > > > > bug? I am using grass-6.3.cvs. > > > > > > > > > > Thanks, > > > > > Boris > > > > > > > > check region extents and resolution ... can you send the output from > > > > g.region -p ? > > > > > > > > Dylan > > > > > > > > > > > > -- > > > > Dylan Beaudette > > > > Soil Resource Laboratory > > > > http://casoilresource.lawr.ucdavis.edu/ > > > > University of California at Davis > > > > 530.754.7341 > > > > > > > > -- > > > > Dylan Beaudette > > Soil Resource Laboratory > > http://casoilresource.lawr.ucdavis.edu/ > > University of California at Davis > > 530.754.7341 > > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.503 / Virus Database: 269.15.33/1133 - Release Date: 11/15/2007 > 8:57 PM > > > No virus found in this outgoing message. > Checked by AVG Free Edition. > Version: 7.5.503 / Virus Database: 269.15.33/1133 - Release Date: 11/15/2007 > 8:57 PM > > _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
