maven wrote: >>> I have a geotiff now, and some cells have a >>> not-expected value, so I want to Interpolation them, and I notice >>> that there is a command named r.fillnull, however the cell >>> to be changed is not null, so I want to :
Hamish: > > try r.null. > | Range of data: min = > -1267650600228229401496703205376.000000 max = 4 | > 2)then I use r.null to set the null value to null: > r.null setnull=-1.26765060022823e+030 > > 3) I use the r.info again to see if it is changed : > > r.info -r map=...@permanent > > min=-1.26765060022823e+030 > max=498.5 .. > It seems that the valuse are not changed to > null. > > I wonder why? probably due to floating point precision issues (why Glynn recommended to use a range instead of an exact value, see http://docs.sun.com/source/806-3568/ncg_goldberg.html ) So going back to the r.mapcalc method, except use less-than some minimum value instead of trying to do an exact equality: r.mapcalc "clean_map = if( dirty_map < -9999, null(), dirty_map)" meaning: if (this is true), then (set it to this), otherwise (set it to this) Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
