On Mon, 2009-06-15 at 11:06 +0100, Laura Poggio wrote: > Dear all, > I am trying to use the QA information of MODIS products. I found that > this analysis can be done in GRASS with r.bitpattern (from Neteler, > 2005 with some examples) or with r.mapcalc . > > From what I understood, the use of r.mapcal seems to be more flexible. > I am just wondering if there are some code examples using the bitwise > operators of mapcalc. I found the following code: > "lst_filt = (lstmap ~ [XX XX XX 00]) || (lstmap ~ [XX XX 0X 01])" > but to me it is not really clear how this works, especially compared > to the code provided (and explained) by Glynn Clements: > r.mapcalc MASK="if((sur_refl_qc_250 / 16) % 16 == 11 , 1, null())" > > Thank you very much for any help. > > Laura
Hi Laura! I am sending you some notes of mine off-list. Also, check... "In the upcoming release of GRASS (version 7) there is an extra module to derive such quality layers called i.modis.qc" ; Yann Chemin, International Rice Research Institute, The Philippines, http://svn.osgeo.org/grass/grass/trunk/imagery/i.modis.qc/i.modis.qc.html Regards, Nikos _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
