defining a grid from latitudes and longitudes read from a file

[Steve Knox <stevek@xxxxxxxxxxxxxxxxxx>]

I have 3 files: one for each of latitudes,longitudes and data
There is no time variable.
I read in the values ok
But I'm getting "**ERROR: dimensions improperly specified: must be a 2D
region"
Isn't my grid a 2D region (iindex by jindx)?

yes? go a
define axis/x=1:1711:1 iindex
define axis/y=1:1711:1 ijindex
define grid/x=iindex/y=jindex my_grid
file/var=my_lon/grid=my_grid longitudes.dat
file/var="skip1,my_lat"/grid=my_grid latitudes.dat
file/var="skip1,skip2,skip3,sand"/columns=4/grid=my_grid soils.txt
set variable/bad=-9999 sand[d=3]
shade sand[d=3], my_lon[d=1], my_lat[d=2]

 **ERROR: dimensions improperly specified: must be a 2D region
          shade sand[d=3], my_lon[d=1], my_lat[d=2]

What am I doing wrong?

Thanks,

Steve Knox
NREL
CSU