Glaciers in Alaska with subsetting by watershed and SASAP region

Glaciers in Alaska were analyzed by watershed and region of Alaska for the State of Alaska Salmon and People (SASAP) project. 188 watersheds and thirteen regions were assessed for number of intersecting glaciers, area covered by glaciers, and other glaciers statistics as described in "Glaciers.ipynb" in this package. Glaciers data is based on the River Analysis Project (RAP) dataset as outlined in "A Riverscape Analysis Tool Developed to Assist Wild Salmon Conservation Across the North Pacific Rim" by Whited, D. C., J. S. Kimball, J. A. Lucotch, N. K. Maumenee, H. Wu, S. D. Chilcote, and J. A. Stanford (2012). Glacier polygons in the RAP dataset were provided directly by the authors and are based on 1990s-era Landsat 4 and 5 satellite data, with methodology outlined in the publication above. Regions are determined by the SASAP project and watersheds are based on HUC8 definitions from the International Joint Commission and sub-sub-drainages from the Canadian National Hydro Network.