[GRASS-user] r.mapcalc trouble

[Tyler Smith]

Hi,

I'm having some trouble with clipping a group of raster maps. I tried
the following:

na_ecoreg is a vector map covering all of north america
clipper is a manually digitized vector map that touches all the areas
of na_ecoreg that I want to clip the rasters with
wc_mean_temp_dry is a worldclim raster map covering the whole area

#-------
v.select ainput=na_ecoreg binput=clipper output=eco_clip
v.to.rast input=eco_clip output=eco_clip use=val value=1
r.mapcalc mean_temp_dry_clip='if(wc_mean_temp_dry && eco_clip,
  wc_mean_temp_dry, null())'
#-------

I've done this for eight raster maps. Some of the maps I've produced
are fine, but others show null raster pixels in the clipped raster
that are not in the source raster map. The null pixels are not present
in the eco_clip raster map either. What could be causing this?

-- 
Regards,

Tyler Smith