San Francisco Vegetation (GGNRA, 2009)

High resolution vegetation polygons mapped by the National Park Service. The vegetation units of this map were determined through stereoscopic interpretation of aerial photographs supported by field sampling and ecological analysis. The vegetation boundaries were identified on the photographs by means of the photographic signatures and collateral information on slope, hydrology, geography, and vegetation in accordance with the Standardized National Vegetation Classification System (October 1995). The mapped vegetation primarily reflects conditions that existed during 1994 and 1995. Several sets of aerial photography were utilized for this project: 1) NOAA 1:24,000 March 1994 Natural Color Prints (Leaf Off) covering Point Reyes NS, the northern portion and southern coastal portions of Golden Gate NRA, and the western two thirds of Mt. Tamalpais State Park; 2) Pacific Aerial Survey 1:24,000 August 1995 Natural Color Prints (Leaf On) covering the southern portions of Golden Gate NRA and the San Francisco Watershed district; 3) Pacific Aerial Survey 1:24,000 November 1995 Natural Color Prints (Leaf Change) covering Samuel P. Taylor State Park and portions of the GGNRA; 4) 1:36,000 August 1991 Natural Color Prints (Leaf On) covering the eastern portion of Mt. Tamalpais State Park; 5) 1:12,000 August 1990 Natural Color Prints (Leaf On) covering Samuel P. Taylor State Park. (Supplemental data set - not interpreted off of); 6) 1:12,000 June 1993 Natural Color Prints (Leaf On) covering coastal portions of Mt. Tamalpais State Park (Supplemental data set - not interpreted off of); 7) Hammon-Jensen-Wallen 1:12,000 August 1996 CIR Prints and Diapositives (Leaf On) covering the Vision Fire Burn Area; 8) 1:12,000 April 1984 CIR Prints were provided to fill in small gaps in the Drakes Bay area; 9) Radman Aerial Surveys 1:12,000 April 1993 Natural Color Prints covering Angel Island; 10) Only the Black and White DOQQ (San Francisco NE) was available for Alcatraz Island. Additionally, supplemental DAIS imagery for October 2001 was acquired after the project was started, which was then used to re-interpret some of the original work. There is an inherent margin of error in the use of aerial photography for vegetation delineation and classification.