Aerial photography creates images that are useful to assess land use and land cover. Traditional aerial photographs are distorted so features in the photographs do not exactly match features on topographic maps. With stereo or digital photography, however, distortions can be corrected so that features in photographs do match features on topographic maps. Such corrected images are called orthophotographs. Various sources of aerial photography may be used during later study phases to assess land use and land cover in the WRIA 1 study area. A description of selected available aerial photography follows.

The Huxley Map Library at Western Washington University in Bellingham has aerial photographs of western Whatcom County for the years 1943, 1947, 1955, 1966, 1976, and 1984. The photos have a scale of either 1:20,000 or 1:40,000 and they may be viewed or copied in the library.

The Washington State Department of Natural Resources (DNR) in Olympia sells aerial photographs at different scales and for different years. The DNR has high-altitude photographs (scale 1:63,360) for 1971, 1974, 1984, and 1991, and low-altitude photographs (scale 1:12,000) for 1969, 1978, 1980, 1983, 1987, 1991, and 1995. The DNR has digital orthophotographs for 1998 (scale 1:63,360), which cover all of WRIA 1 excluding national forest lands. These digital orthophotographs are in the process of being converted to a scale of 1:24,000 to match 1:24,000-scale USGS topographic maps.

The USGS sells digital orthophotographs (scale 1:24,000) for 1994. As part of the National Aerial Photography Program, the USGS has aerial photographs available for WRIA 1 for 1990. These photos have a base scale of 1:40,000, but photos can also be obtained at 1:20,000 and 1:10,000 scales. Instructions for purchase of these and other photographs may be found at http://edcwww.cr.usgs.gov/webglis/index.html.

Every six months, the USGS reissues a CD-ROM with a database of aerial photography projects that meet specified criteria over a given geographic area of the United States and its territories. The database is called the Aerial Photography Summary Record System (APSRS). A second database with contributor information is also included. The CD-ROM and a license for its use may be purchased from the USGS Earth Science Information Center (1-888-ASK-USGS).