Good day, I am having problems reading HDF files. The files contain TRMM satellite data from the GSFC DAAC and were downloaded in July 2004. I could not find documentation on whether the files were HDF4 or HDF5 format. IDL version 6.1.1 OS: Linux (RedHat) Release: 2.6.10-1.12_FC2 I found reference to similar errors but no solution. Does anyone here know what may the cause of the error and a solution? I know that HDF libraries are present but do not seem to be able to read the files. Thanks in advance. Arlene Laing Here is what I get when I run hdf_info on the file: ----------------------------------------------------------------------- IDL> hdf_info, '2A25.990606.8754.5.HDF' *****BEGINNING OF HDF_INFORMATION***** ================================================================================ FILENAME : 2A25.990606.8754.5.HDF ================================================================================ # of HDF free palettes = 0 ================================================================================ # of HDF-AN file descriptions = **** # of HDF-AN data descriptions = **** # of HDF-AN file labels = **** % Loop limit expression too large for loop variable type. . % Execution halted at: HDF_INFO 80 /usr/common/idl_6.0/examples/data_access/sdf/hdf_inf o.pro ------------------------------------------------------------------ Here is the code for reading the file: ------------------------------------------------ sd_id=HDF_SD_START(filename,/read) ------------------------------------------------ Here is the result when I try to run the code ------------------------------------------------ % Loaded DLM: HDF. % HDF_SD_START: Unable to start the HDF-SD interface. ------------------------------------------------