[ferret_users] projections and multiple input files

[Martinho MA <martinho@xxxxxxxxx>]

Hello,
I have two files, one includes sst and the other longitude and latitude, 
see ncdump:
>ncdump -h 200512271200.nc
netcdf 200512271200 {
dimensions:
       time = 1 ;
       depth = 1 ;
       latitude = 1024 ;
       longitude = 1024 ;
variables:
       short sea_surface_temperature(time, latitude, longitude) ;
               sea_surface_temperature:long_name = "sea surface 
temperature" ;
               sea_surface_temperature:units = "K" ;
               sea_surface_temperature:scale_factor = 0.01 ;
               sea_surface_temperature:add_offset = 0.f ;
               sea_surface_temperature:valid_min = 0s ;
               sea_surface_temperature:valid_max = 32767s ;
               sea_surface_temperature:missing_value = 32767s ;
               sea_surface_temperature:_FillValue = 32767s ;
... etc      
ncdump -h grid.nc
netcdf grid {
dimensions:
       latitude = 1024 ;
       longitude = 1024 ;
variables:
       float latitude(latitude, longitude) ;
               latitude:long_name = "latitude" ;
               latitude:units = "degrees_N" ;
       float longitude(latitude, longitude) ;
               longitude:long_name = "longitude" ;
               longitude:units = "degrees_E" ;
}


to plot ssh I use fill sea_surface_temperature[d=1],longitude,latitude

But now, I would like to use some map projection... I checked the ferret 
demo:
http://ferret.wrc.noaa.gov/Ferret/Demos/mp_demo/mp_demo.html

SO, I think I should so:
SET REGION/X=-15:-8/Y=35:45/l=1
GO mp_lambert_cyl
GO mp_aspect
fill SEA_SURFACE_TEMPERATURE,LONGITUDE[d=1],latitude[d=1]

This isnt working, and even without the projection, I got and error:
fill SEA_SURFACE_TEMPERATURE,LONGITUDE[d=1],latitude[d=1]
**ERROR: illegal limits: "SEA_SURFACE_TEMPERA..." is not in the range 
X=-15:-8
         Axis extremes are X=0.5:1024.5

I guess this is because I have dimension longitude and latitude in my 
sst variable, and then I want to use longitude and latitude from other 
file.!?
How can I solve this?
I am quite a basic ferret user, and maybe the question is basic too...

Thanks
MMA