Hi Socorro:
AFAIU, standard WRF netcdf output is incomplete in some ways, and the WRF 
postprocessor adds the missing info and converts to GRIB. So until we can 
improve the netcdf output, it seems that the GRIB output may be preferred. 
Which BTW, the IDV should be able to read just fine.
Having said that, Im not positive that translating sigma-to-height is one if 
the missing pieces. A sample CF file using sigma coordinates that I think works 
in the IDV is
 http://www.unidata.ucar.edu/software/netcdf/examples/Sigma_LC.nc 
John
Socorro Medina wrote:
Hello All,
I'm new to IDV and I'm trying to display WRF output.  The file that I 
have is in netcdf format. The vertical coordinates of the output are 
sigma-coordinates. I'm able to display plan-views OK, however I'm not 
able to make vertical cross-sections. I think that it may be because the 
file is not properly telling IDV how to go from sigma coordinates to 
height coordinates. I was wondering if anybody have had this problem 
before and/or if anybody has a sample netcdf file in sigma coordinates 
of which IDV is able to correctly display vertical cross-section in 
height coordinates.
Thank you,
Socorro Medina