Science Inventory



Skirvin, S. M., S. E. Drake, J. K. Maingi, S. E. Marsh, AND W G. Kepner. AN ACCURACY ASSESSMENT OF 1997 LANDSAT THEMATIC MAPPER DERIVED LAND COVER FOR THE UPPER SAN PEDRO WATERSHED (U.S./MEXICO). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-00/097 (NTIS PB2001-104914), 2000.


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.


High-Resolution airborne color video data were used to evaluate the accuracy of a land cover map of the upper San Pedro River watershed, derived from June 1997 Landsat Thematic Mapper data. The land cover map was interpreted and generated by Instituto del Medio Ambiente y el Besarrollo Sustentable del Estado de Sonora (IMADES), Hermosillo, Sonora and supplies to the Arizona Remote Sensing Center at the University of Arizona for evaluation. Map pixel size had been increased from 30 to 60 meters to match the 1973, 1986, and 1992 North American Landscape Characterization (NALC) land cover maps produced from Landsat MSS data.

The airborne color video data included six flight lines acquired 2-5 May 1997 over the San Pedro watershed in the U.S. GPS time and coordinate information encoded on the video tapes were used to generate GIS point coverages of video frames covering the upper San Pedro. A total of 527 video sample points were drawn randomly from a subset of 4567 frames falling on areas of uniform cover classes at least 180 meters square. Sample points were stratified by cover class area, with a minimum sample of 24 points of classes of small areal extent. The Water class was extremely rare (covering less than 0.1% of the study area) and was excluded from video data analysis for lack of data. Video sample points were reviewed by an experienced interpreter who assigned land cover class labels based on available descriptions. Map and video labels were compared to generate a classification error matrix, which produced an overall map accuracy of about 72%.

Record Details:

Product Published Date: 12/21/2000
Record Last Revised: 12/22/2005
Record ID: 63261