In order to gather information about historical floating kelp presence in North Puget Sound and the Strait of Georgia, the Washington State Department of Natural Resources is analyzing historical color-infrared aerial imagery captured in Whatcom and Skagit Counties in 1995 and 1996, respectively. As a component of this process, imagery is “masked” by creating polygons that delineate areas of potential floating kelp presence, excluding land, deep water, and other non-floating-kelp nearshore and intertidal vegetation. Imagery is clipped to masks, and then masked areas are classified using spectral indexing, segmentation, and ISO clustering to identify floating kelp canopy area. This layer contains the masks used to clip the imagery for Skagit County in 1996. Contact nearshore@dnr.wa.gov for more information or with questions pertaining to this data.