I've run into a problem when calling ENVI_PROJ_CREATE from and IDL procedure. I use ENVI5.1 + IDL8.3 and never run IDL code before. Here is the code: pro test_batch_modis_conversion_l2_swath compile_opt idl2 modis_swath_file = 'C:\MCTK_Input\MYD04_3K.A2002247.0300.006.2014195232718' ;The specified output location MUST end in the appropriate path ;separator for your OS output_location = 'E:\Downloads\Aerosol retrieval' output_rootname = 'test' swath_name = 'mod_3k' sd_names = ['Optical_Depth_Land_And_Oecan','Image_Optical_Depth_Land_And_Oecan','Land_sea_Flag'] ;Output method schema is: ;0 = Standard, 1 = Projected, 2 = Standard and Projected out_method = 1 output_projection = envi_proj_create(/geographic) Here is the output: IDL> test_batch_modis_conversion_l2_swath % Compiled module: TEST_BATCH_MODIS_CONVERSION_L2_SWATH. % Attempt to call undefined procedure/function: 'ENVI_PROJ_CREATE'. % Execution halted at: TEST_BATCH_MODIS_CONVERSION_L2_SWATH 13 C:\Users\hp\IDLWorkspace83\Default\test_batch_modis_conversion_l2_swath.pro % $MAIN$ Has anyone else encountered this? What is the fix? Thanks, Qingqing