Current Distribution of Sagebrush and Associated Vegetation in the Columbia Basin and Southwestern Regions

A new regional dataset was produced using decision tree classifier and other techniques to model landcover. Multi-season satellite imagery (Landsat ETM+, 1999-2003) and digital elevation model (DEM) derived datasets (e.g. elevation, landform, aspect, etc.) were utilized to derive rule sets for the various landcover classes. Eleven mapping areas, each characterized by similar ecological and spectral characteristics, were modeled independently of one another. An internal validation for modeled classes was performed on a withheld 20% of the sample data to assess model performance. Results of the validation will be presented in the final report and are not available at this time. Mapping area models were mosaicked to create the Columbia Basin Regional Dataset (Idaho, Oregon and Washington), which was subsequently combined with the Southwest Regional Gap Landcover Dataset to create the final seamless 8 state regional landcover map. The final map contains 126 Landcover classes (103 NatureServe Ecological Systems, 7 NLCD and 16 non-native vegetation classes) and has a minimum mapping unit (MMU) of approximately 1 acre.