While we discuss it, another good step you want to apply before doing the actuall stitch is to trim the rasters' area by a couple of pixels before hand. Usually the borders is full with pesky pixel with distorsions/noise, which might contaminate your mosaic.
N On Fri, Nov 15, 2013 at 10:28 PM, Markus Neteler <[email protected]> wrote: > On Fri, Nov 15, 2013 at 4:12 PM, Nikos Alexandris > <[email protected]> wrote: >> nyflyer wrote: >>> I've been trying to use the i.image.mosaic command in GRASS 6.4.1 in >>> Ubuntu > > Please note that 6.4.1 isn't particularly new. > > http://trac.osgeo.org/grass/wiki/Release/6.4.2-News > "Between 6.4.1 and the current 6.4.2 more than 770 updates have been applied." > > http://trac.osgeo.org/grass/wiki/Release/6.4.3-News > "Over 830 new features and bug-fixes have been applied since 6.4.2. " > > (and it is time to get 6.4.4 out...) > >>> to stitch two raster image files (technically I'm trying to stitch only >>> the blue channel of an RGB truecolor image) but I'm just getting a blank >>> image >>> file as the output. > > You have the computational region right? > ... >> --%<--- >>> | Total Cells: 28707984 >>> | Projection: UTM (zone 17) >>> | N: 3280373.34673833 S: 3280265.18938071 Res: 0.02067228 >>> | E: 372335.90758975 W: 372236.78889019 Res: 0.01806428 > > A remark: The current resolution is hence 1-2cm given that you are in UTM? > > BTW: You may consider to check if you do not want to have square > pixels (and if so, why they aren't). > > Markus > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
