Although the software, called "Animal Movement," was developed to study animal migration and movement patterns, the principles underlying it also apply to the study of movement in general. Animal Movement is an extension that runs under versions 3.0 through 3.3 of ArcView, a family of desktop geographic information system (GIS) software applications that enable users to visualize, analyze, and manipulate spatial information. The Animal Movement extension includes more than 40 functions specifically designed to help analyze movements and is available on the Internet as a free download. A federally subsidized training program in the use of the software is offered to public safety personnel at the Northeast Counterdrug Training Center at Fort Indiantown Gap National Guard Training Center in Pennsylvania. Two different 40-hour, 5-day classes offer an introduction to the basics of crime mapping and advanced GIS for tactical crime analysis, which uses Animal Movement and other tools. Animal Movement's use in the field has generally been most effective when applied in conjunction with other tools and when a case involves 10 or more related offenses.