Thanks for the important clarification. Do you think it would be useful to add this information in the manual of r.mask?
On Wed, 2008-01-23 at 04:18 +0000, Glynn Clements wrote: > [EMAIL PROTECTED] wrote: > > > Thank you for the attention Moritz. > > > > I understand MASK as a boolean map with (let's say) "1" > > (for true) and "0" (for false). > > > > The r.info (the one I provided in my previous e-mail) is > > about the raster data I want to use to create a MASK and > > not the MASK itself. > > > > Should I understand that only "integer" raster data are > > suitable to create a MASK? > > The mask is read as an integer map. If MASK is actually a > floating-point map, the values will be converted to integers using the > map's quantisation rules (this defaults to round-to-nearest, but can > be changed with r.quant). > > Your NDVI20060.35 map has a range of 0.001304 to 0.349991, so all of > those values will be rounded to zero. > > > I understand (reading the r.mapcalc functionality) that one > > can use any kind of raster data (floating point) and create > > a MASK which contains a "1" for the pixels that have any > > value besides "NULL". > > > > So I expected to have a "1" wherever there was a value in > > my NDVI2006 file. > > > > Maybe I use it wrong(?) > > > > Should I specify to assign a value of "1" for all non-NULL > > source pixels? > > > > I'll try with "mask = a != 0" as described in the r.mapcalc > > manual. > > If you want to create a mask based upon null/non-null, use e.g.: > > r.mapcalc "MASK = !isnull(inmap)" > -- Nikos Alexandris . Department of Remote Sensing & Landscape Information Systems Faculty of Forestry & Environmental Sciences, Albert-Ludwigs-University Freiburg . Tel. +49 (0) 761 203 3697 / Fax. +49 (0) 761 203 3701 / Skype: Nikos.Alexandris . Address: Tennenbacher str. 4, D-79106 Freiburg i. Br., Germany
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