For more information about this data set, see the peer-reviewed journal article:

Sanderson, E. W., M. Jaiteh, M. A. Levy, K. H. Redford, A. V. Wannebo, and G. Woolmer. 2002. The Human Footprint and the Last of the Wild. BioScience 52 (10): 891-904. https://doi.org/10.1641/0006-3568(2002)052[0891:THFATL]2.0.CO;2.