Accuracy assessment for the US Geological Survey Regional Land-Cover Mapping Program: New York and New Jersey region

The U.S. Geological Survey, in cooperation with other government and privat e organizations, is producing a conterminous U.S. land-cover map using Land sat Thematic Mapper 30-meter data for the Federal regions designated by the U.S. Environmental Protection Agency. Accuracy assessment is to be conduct ed for each Federal region to estimate overall and class-specific accuracie s. In Region 2, consisting of New York and New Jersey, the accuracy assessm ent was completed for 15 land-cover and land-use classes, using interpreted 1:40,000-scale aerial photographs as reference data. The methodology used for Region 2 features a two-stage, geographically stratified approach, with a general sample of all classes (1,033 sample sites), and a separate sampl e for rare classes (294 sample sites). A confidence index was recorded far each land-cover interpretation on the 1:40,000-scale aerial photography. Th e estimated overall accuracy for Region 2 was 63 percent (standard error 1. 4 percent) using all sample sites, and 75.2 percent (standard error 1.5 per cent) using only reference sites with a high-confidence index. User's and p roducer's accuracies for the general sample and user's accuracy for the sam ple of rare classes, as well as variance for the estimated accuracy paramet ers, were also reported. Narrowly defined land-use classes and heterogeneou s conditions of land cover are the major causes of misclassification errors . Recommendations for modifying the accuracy assessment methodology for use in the other nine Federal regions are provided.