Hi all, I am seriously hoping someone out there can help me with this .  I am trying to georeference MODIS L1B hdf files using envi batch mode. I found a bit about this on the net (particularly the Ocean Color forums and in here for other instruments) and have tried to emulate their method, although as they wern't using L1B, I think I am encountering some sort of additional issue. What I have so far is pasted below. This actually does output a georeferenced-looking file, however the values are somewhat different to the result if I georeference it with ENVI normally.  I think the issue is either in making the GLT, or in the georeferencing itself. (nb.  I also tried the MODIS Conversion Toolkit, which georeferences the file just fine, but as it converts it to a .img is not suitable for what I need) Any help greatly appreciated, Cheers, Helen open lon file     ENVI_OPEN_DATA_FILE, filename, r_fid=x_fid, /hdf_sd, hdfsd_dataset=1, hdfsd_interleave=0       if (x_fid eq -1) then begin        envi_batch_exit        return       endif     ENVI_FILE_QUERY, x_fid, ns=xns, nl=xnl, nb=xnb     x_pos=lindgen(xnb)     xdims=[-1L, 0, xns-1, 0, xnl-1]     ;open lat file     ENVI_OPEN_DATA_FILE, filename, r_fid=y_fid, /hdf_sd, hdfsd_dataset=0, hdfsd_interleave=0       if (y_fid eq -1) then begin        envi_batch_exit        return      endif     ENVI_FILE_QUERY, y_fid, ns=yns, nl=ynl, nb=ynb     y_pos=lindgen(ynb)     ydims=[-1L, 0, yns-1, 0, ynl-1]     ;open file     ENVI_OPEN_DATA_FILE, filename, r_fid=therm_fid, /hdf_sd, hdfsd_dataset=4, hdfsd_interleave=0       if (therm_fid eq -1) then begin        envi_batch_exit        return       endif     ENVI_FILE_QUERY, therm_fid, ns=ns, nl=nl, nb=nb, data_type=data_type, bnames=bnames     pos=lindgen(nb)     dims=[-1L,0, ns-1, 0, nl-1] ;CD TO THE OUTPUT DIRECTORY cd, Outputdir ;  Figure out what UTM zone we're in. lat_data=envi_get_data(fid=y_fid, dims=ydims, pos=0) lon_data=envi_get_data(fid=x_fid, dims=xdims, pos=0) lat_lon=[lat_data, lon_data] zone = fix(31.0 + lat_lon[1]/6.0) south = (lat_lon[0] lt 0) nlat=  n_elements(lat_data) nlon = n_elements(lon_data) lat=mean(lat_data)      ;find the average (so approx center of image) to define the UTM zone. lon=mean(lon_data) LongTemp = (Lon+180)-fix((Lon+180)/360)*360-180; // -180.00 .. 179.9 ZoneNumber = FIX((LongTemp + 180.0)/6.0) + 1 if Lat GE 56.0 AND Lat LE 64.0 AND LongTemp GE 3.0 AND LongTemp LE 12.0 then ZoneNumber = 32 ;special zones for Svalbard IF lat GE 72.0 and lat LE 84.0 then begin         if longtemp ge 0.0 and longtemp lt 9.0 then zonenumber =32         if longtemp GE 9.0 and longtemp lt 21.0 then zonenumber = 33         if longtemp ge 21.0 and longtemp lt 33.0 then zonenumber = 35         if longtemp ge 33.0 and longtemp lt 42.0 then zonenumber = 37 ENDIF south = (lat lt 0) ;  Make the GLT. zone=zonenumber envi_file_query, therm_fid, sname=sname out_name1='GLT_file_'+fname ;pixel_size=[1000.0, 1000.0] rotation=0.0 i_proj = envi_proj_create(/geographic) o_proj = envi_proj_create(/utm, zone=zone, south=south)     envi_glt_doit, i_proj=i_proj, o_proj=o_proj, out_name=out_name1, r_fid=glt_fid,$     x_fid=x_fid, y_fid=y_fid, x_pos=0, y_pos=0,pixel_size=pixel_size, rotation=rotation ;therm_fid contains all the emissive bands.We only need bands 29-32 for the SO2 retrieval. t_fid= [therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid, $ therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid,therm_fid] t_pos=[11,10,9,8] ;  Georeference the image from the GLT. out_name2=fname+'georefferenced' envi_doit, 'envi_georef_from_glt_doit', fid=t_fid, $    glt_fid=glt_fid, out_name=out_name2, pos=t_pos, $    subset=dims, r_fid=r_fid