Roberto, I tried out the update to v.surf.bspline and now I CAN do an interpolation using a vector attribute column.
However, when I use a z-value for interpolation and then use an attribute column for exactly the same values, I get very different interpolations. For example, I ran the following two interpolations, the first using the z-value (layer 0) and the second using the attribute column that is used for the z-value (layer 1) v.surf.bspline [EMAIL PROTECTED] raster=test_interpolation_z sie=4 sin=4 type=bicubic lambda_i=1 layer=0 v.surf.bspline [EMAIL PROTECTED] raster=test_interpolation_attr sie=4 sin=4 type=bicubic lambda_i=1 layer=1 column=CAL_MID Then I made a difference map of the two results r.mapcalc 'test_interpolation_diff=test_interpolation_z - test_interpolation_attr' Finally, I ran r.univar to summarize the differences. As you can see there is a big difference between the 2 maps. GRASS 6.3.cvs (Europe_ll_wgs84):~ > r.univar test_interpolation_diff 100% total null and non-null cells: 21758946 total null cells: 0 Of the non-null cells: ---------------------- n: 21758946 minimum: 280.434 maximum: 24343.5 range: 24063.1 mean: 6819.02 mean of absolute values: 6819.02 standard deviation: 5566.97 variance: 3.09912e+07 variation coefficient: 81.6389 % sum: 148374632036.5238342285 I'm not sure which is the more accurate, but it LOOKS like the one using z-values is the correct one. I made a jpg output from each map and attach them here for visual comparison. It is clear that they are very different, even though ostensibly using the same data. Also, in both cases the interpolation does not respect a MASK. I like this module a lot and hope that this can help to improve it. Michael __________________________________________ Michael Barton, Professor of Anthropology Director of Graduate Studies School of Human Evolution & Social Change Center for Social Dynamics & Complexity Arizona State University phone: 480-965-6213 fax: 480-965-7671 www: http://www.public.asu.edu/~cmbarton On 10/19/07 9:35 AM, "Michael Barton" <[EMAIL PROTECTED]> wrote: > Excellent! Thanks again. > > Michael > > > On 10/19/07 9:34 AM, "Roberto Antolin" <[EMAIL PROTECTED]> > wrote: > >> Hello Michael >> >> Michael Barton escribió: >>> Thanks Roberto. Is it in the CVS now? >> >> Yes, it is. Sorry, I forgot to tell you :) >> Please, let me now if it is ok or there is still something wrong. >> >> Roberto. >> >> > > __________________________________________ > Michael Barton, Professor of Anthropology > Director of Graduate Studies > School of Human Evolution & Social Change > Center for Social Dynamics and Complexity > Arizona State University > > phone: 480-965-6213 > fax: 480-965-7671 > www: http://www.public.asu.edu/~cmbarton >
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