I also tried subsetting using the Export method to ENVIRaster but get the following error message: % Attempt to call undefined method: 'ENVIRASTER::EXPORT'.

Hello Sam, I believe the reason you're getting the error is that the creation of a new ENVI raster object (i.e., the line below) changed from version 5.0 to 5.1. The online example reflects ENVI 5.1. newRaster = ENVIRaster(origData, URI=newFile, NBANDS=1) However, I don't think you need this line or even the GetData method. You can just use the Subset method on the source raster to define your spectral and spatial subset. I created small program for you (below) which *should* work with ENVI 5.0...I don't have a copy of this version to test it with. The following example creates a spectral subset of the first band and a spatial subset of the first 200 pixels in the upper-left corner of the source images, then exports the results to GeoTIFF files in your system's temporary directory. Please try this. You'll need to change the File_Search line to point to your own directory and filenames. PRO SubsetExportToGeoTIFF COMPILE_OPT IDL2 e = ENVI(/headless) files = File_Search('C:\MyData', 'Images*.tif') For i=0, N_Elements(files)-1 DO BEGIN raster = e.OpenRaster(files[i]) newFile = e.GetTemporaryFilename() SubRaster = raster.Subset(BANDS=[0], SUB_RECT=[0,0,200,200]) SubRaster.Export, newFile, 'TIFF' Endfor END

Hi Jwolfe, thanks for the reply. ; following up to this line SubRaster = raster.Subset(BANDS=[0], SUB_RECT=[0,0,200,200]) ; works successfully and creates an ENVI Raster! help,subraster SUBRASTER ENVIRASTER ; but I cannot seem to use it properly SubRaster.Export, newFile, 'TIFF' % Attempt to call undefined method: 'ENVIRASTER::EXPORT'. _________________________________________________________ I might have to wait for ENVI 5.1. for this to work properly :/ In the meantime I am studying the GeoTIFF specification http://www.remotesensing....f/spec/contents.html So that I can read, subset, update georeference information, and write through IDL. ; read img=READ_TIFF(filepath, GEOTIFF=GeoKeys) ; subset subset = img[x_lo:x_hi,y_lo:y_hi] ; update georeference information ; todo [study the contents of geokeys structure (section 2.7 of GeoTIFF specification), I will post final results for Landsat 8.] ; write WRITE_TIFF, outpath, subset, GEOTIFF=updated_GeoKeys

It looks like we changed the Export method from 5.0 to 5.1 as well. It used to be a method off the ENVI object, and now it's a method off the ENVIRaster object. Since you are using version 5.0, please replace this line: SubRaster.Export, newFile, 'TIFF' with this: e.ExportRaster, SubRaster, newFile, 'TIFF' The resulting files will still have .dat extensions, but they are actually GeoTIFFs.

This created a new subset geotiff with my version of ENVI but the subset is larger than the SUB_RECT pixel coordinates that I specified in this line. subRaster = raster.Subset(BANDS=[0], SUB_RECT=[x1,x2,y1,y2]) I cannot figure out why! I even tested that the pixel coordinates were correct by subsetting with (read/write)_tiff and updating the geokeys (i.e. changing the 'ModelTiePointTag' in the case of Landsat 8 data).. which incidently is a working solution, so that's good. Thanks for your help!