DISCUSSION: I understand that the IDL GEOPACK DLM was developed and is distributed by a third party developer. This DLM is not supported by Exelis VIS. However, in case it can help, here are some general hints for getting a DLM to work with an IDL installation: 1) Be sure that the IDL DLM shared library file (a "*.so" file for UNIX type operating systems or "*.dll" for Windows systems) was created for use with the IDL version/bit-version (32 or 64-bit) that you are running on your operating system. The provider of the DLM would be able to provide you with this information. 2) Be sure that the *.dlm file and the associated shared library file are both located in a directory that is recognized by the IDL session as part of its DLM search path setting (IDL_DLM_PATH preference or the underlying !DLM_PATH system variable setting). You can see your current DLM search path settings by issuing the following commands: HELP, /PREFERENCES, NAME='IDL_DLM_PATH' PRINT, !DLM_PATH By default, new DLM files added into the matching platform-specific binary subdirectory of your IDL installation will be recognized by the IDL session. For example for 64-bit IDL on Windows, the default directory for DLM files is: C:\Program Files\exelis\idl84\bin\bin.x86_64\ On Linux and Solaris: /usr/local/exelis/idl84/bin/bin.[platform]/ (where "[platform]" is the specific platform name, such as "linux.x86_64" or "solaris2.sparc64") On Mac OS X: /Applications/exelis/idl84/bin/bin.darwin.x86_64/ If you need to store your DLM files in a different, non-default directory location, modify your IDL_DLM_PATH preference, either through the IDL Workbench Preferences dialog or through a command issued at the IDL > command prompt, for example, on Linux (where ~ is the user's home directory location; notice also the use of the string token to ensure that the default IDL DLM search path is included in the customized path): mydlmdir = "~/myidl" PREF_SET, 'IDL_DLM_PATH', ''+PATH_SEP(/SEARCH_PATH)+mydlmdir, /COMMIT 3) For consistency, be sure that the DLM file names are in all lower case letters. Additionally, be sure that both the *.dlm file and its associated shared library file have at least read permissions for all users. 4) After ensuring the compatible DLM files are located in your IDL DLM search path, you can verify that the DLM is known to the IDL session and its current load state by issuing an IDL command like: HELP, /DLM You can also specify a DLM by name by issuing a command like (where PNG in this case refers to the IDL PNG DLM): HELP, /DLM, NAME='PNG' ( See also: http://www.exelisvis.com/docs/HELP.ht... ) 5) Additional information about IDL DLMs can be found in the IDL Help system or on the Exelis VIS web site Documentation Center: http://www.exelisvis.com/docs/DLM.html