Digital vegetation database and map report for Blue Ridge Parkway

Jordan, Thomas; Madden, Marguerite

This report describes the vegetation mapping procedures employed by the University of Georgia Department of Geography’s Center for Geospatial Research (CGR), for the Blue Ridge Parkway (BLRI) in the Appalachian Highlands Inventory and Monitoring Network (APHN) of the National Park Service under Cooperative Agreement No. H5028 01 0651, entitled, “Digital Vegetation Databases and Maps for National Park Service Units in the Appalachian Highlands and Cumberland/ Piedmont Networks.” The Blue Ridge Parkway is a national scenic highway that winds 750 kilometers (469 miles [mi]) along the crests of the Southern Appalachians in North Carolina and Virginia. The park encompasses 33,483 hectares (82,704 acres [ac]) within a 1,765 kilometer- (1,097 mi-) long boundary (as of September 9, 2008). A total of 128 different vegetation associations, communities and other classes were interpreted for Blue Ridge Parkway using manual methods from 1:16,000-scale stereo color infrared aerial photographs acquired in 2002, 2003 and 2005. For this project, vegetation associations, which include both understory and herb layers in their descriptions, were interpreted from the aerial photographs by inferring the community based on the overstory/canopy characteristics, supplemented with field work. In addition to the mapped area of the park of 34,626 hectares (85,562 ac), a buffer area, extending 400 meters (1,312 feet [ft]) outside of the park (total area is 63,253 hectares or 156,234 ac) was mapped using a more general classification system of land use and land cover; field work did not include the buffer area. Consequently, the total area mapped for Blue Ridge Parkway, including the park and buffer was 100,108 hectares (247,266 ac). Using a minimum mapping unit of 0.5 hectares (MMU = 0.5 hectares [1.2 ac]), polygons representing areas of relatively uniform vegetation were delineated and annotated on clear plastic overlays registered to the aerial photographs. Polygons were labeled according to the dominant vegetation community. Where the polygons were not uniform, second and third vegetation classes were added. Further, a number of modifier codes were employed to indicate important aspects of the polygon that could be interpreted from the photograph (for example, burn condition). The polygons on the plastic overlays were then corrected using photogrammetric procedures and converted to vector format for use in creating a geographic information system (GIS) database for the park. In addition, high resolution color-infrared (CIR) orthophotographs were created from the original aerial photographs for use in the GIS. Upon completion of the GIS database (including vegetation, orthophotos and updated roads and hydrology layers), both hardcopy and softcopy maps were produced for delivery. Metadata for the database includes a description of the vegetation classification system used for the park, summary statistics and documentation of the sources, procedures and spatial accuracies of the data. At the time of this writing, the accuracy assessment of the vegetation mapping is underway but has not yet been completed for this park. Thus, those procedures and results will be provided in a separate report.

Digital vegetation database and map report for Blue Ridge Parkway

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