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AN ACCURACY ASSESSMENT OF 1992 LANDSAT-MSS DERIVED LAND COVER FOR THE UPPER SAN PEDRO WATERSHED (U.S./MEXICO)
Citation:
Maingi, J. K., S. E. Marsh, W G. Kepner, AND C M. Edmonds. AN ACCURACY ASSESSMENT OF 1992 LANDSAT-MSS DERIVED LAND COVER FOR THE UPPER SAN PEDRO WATERSHED (U.S./MEXICO). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-02/040 (NTIS PB2002-107521), 2002.
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
The utility of Digital Orthophoto Quads (DOQS) in assessing the classification accuracy of land cover derived from Landsat MSS data was investigated. Initially, the suitability of DOQs in distinguishing between different land cover classes was assessed using high-resolution airborne color video data. A cross-tabulation of the analyst's DOQ labels and the reference video label was produced and had an overall accuracy of 92%. This indicated that the DOQ data could be used to identify and distinguish between the different land cover classes.
A 1992 land cover map for the Upper San Pedro Watershed was available for accuracy assessment. The map was interpreted and generated by Instituto del Medio Ambiente y el Desarrollo Sustentable del Estado de Sonora (B4ADES), Hermosillo, Sonora. The Environmental Protection Agency (EPA) supplied Arizona Remote Sensing Center (ARSC) with approximately 60 DOQs for 1992. Most of the land cover classes were fairly well represented in the DOQs and covered between 24% and 4 1 % in eight out of ten land cover classes. Only the Barren and Agriculture classes were poorly represented in the available DOQs covering 5.3% and 14.2% of the map area, respectively.
A total of 457 sample points was used for the accuracy assessment. Allocation of sample points to land cover classes was through stratified (by land cover class area) random sampling, with a 20-sample minimum for the smallest classes. Map labels for the sample points were compared with reference DOQ labels and an error matrix generated. An overall classification accuracy of about 75% was obtained.