Software Licenses

All software produced by CUSPA (e.g. UrbanSim and Opus) is covered by the terms of the GNU General Public License, as stated in the following excerpt that appears at the top of every source file in our code base:

 # UrbanSim software. Copyright (C) 1998-2007 University of Washington
 # 
 # You can redistribute this program and/or modify it under the terms of the
 # GNU General Public License as published by the Free Software Foundation
 # (http://www.gnu.org/copyleft/gpl.html).
 # 
 # This program is distributed in the hope that it will be useful, but WITHOUT
 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 # FITNESS FOR A PARTICULAR PURPOSE. See the file LICENSE.html for copyright
 # and licensing information, and the file ACKNOWLEDGMENTS.html for funding and
 # other acknowledgments.

Users may contribute packages under GPL, LGPL, or any other GPL-compatible license. If LGPL, they may then also use those packages in proprietary software as well (the package itself would be open source, but LGPL allows it to be used as a library in a proprietary application). There's no need for a special API or the like - any LGPL package can be used in a GPL application.

We recommend that contributors license their packages either under GPL or LGPL, or if necessary, under some other GPL-compatible license.

Here is a long list of open source licenses, noted with which ones are compatible with GPL: http://www.gnu.org/licenses/license-list.html

Also of interest is this article on [Why you shouldn't use the Library GPL for your next library].

Documentation Licenses

User documentation (including the Opus/UrbanSim Users Guide, and tutorials) are licensed under the GNU Free Documentation License: http://www.gnu.org/licenses/licenses.html#FDL