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EVALUATING SOIL EROSION PARAMETER ESTIMATES FROM DIFFERENT DATA SOURCES
Citation:
Senay, G., S M. Cormier, AND B Subramanian. EVALUATING SOIL EROSION PARAMETER ESTIMATES FROM DIFFERENT DATA SOURCES. Presented at National Conference on Environmental Problem Solving With Geographic Information Systems, Cincinnati, OH, September 22-24, 1999.
Description:
Topographic factors and soil loss estimates that were derived from thee data sources (STATSGO, 30-m DEM, and 3-arc second DEM) were compared. Slope magnitudes derived from the three data sources were consistently different. Slopes from the DEMs tended to provide a flattened surface with large areas having 0.0% values. The 3-arc second DEM generally produced a lower slope estimate than either the STATSGO or 30-m DEM. Slopes from the 30-m DEM fell between the 3-arc second and the STATSGO. Thus, the STATSGO database provided a higher slope estimate than either of the two DEM sources. However, slopes from the 30-m DEM and the STATSGO were more comparable than the slope estimates from 30-m and 3-arc second DEMs. For example, 0.0, 10.0, and 20.0% slope classes from the 30-m DEM showed mean values of 0.0, 4.0, and 6.0%, respectively with the 3-arc second DEM, and 4.0, 18.0, and 24.0% respectively with the STATSGO. Along with the slope differences, potential erosion estimate trends varied between the data sets although the soil loss differences were higher than the slope differences. A recommendation was made to validate slope and erosion estimates using field data; however, it appeared that STATSGO may be more reliable than the two data sets for smaller slopes and either STATSGO or the 30-m DEM may be used for higher slopes. Due to the ease of GIS in combining data from various sources, the importance of a thorough understanding of data accuracy standards and their limitations and intended use were highlighted.