From the site: "This raster dataset has been created using "Pennsylvania Land Cover dated 1992" developed by the EROS Data Center for EPA Federal Region III (see metadata entitled "Land Cover 1992 EPA Federal Region III.pdf") and Landscape Blocks as originated by The Nature Conservancy. Using an inside buffer of 18 meters on the Landscape Blocks a new shapefile was created in order to create a 30 meter area between the blocks to represent roads. Grasslands vegetation cover (Hay/Pasture) from the 1992 land Cover was reclassified and then the road buffered landscape blocks were combined with the raster to assign a value of "0" to areas in the Grasslands land cover that overlap with the road buffers. Acreage of the grasslands vegetation was calculated and the data was reclassified based on conservation value as follows: Acreage Conservation Value 0-25 0 25-160 1 160-250 3 250-400 4 >400 5 Conservation values were determined by experts gathered by Natural Lands Trust through SmartConservation®. This data set is one of several that have been combined to create an overall terrestrial resources conservation value raster for the expanded piedmont ecoregion. Therefore the values were determined as a relative rank, comparable in value only to the other input terrestrial resources data. Conservation value ranges from 1 - 10 with 10 being the highest value."