What is the NLCD 1992/2001 Retrofit Land Cover Change Product?
Although one of the guiding principles of the NLCD 2001 design was to maintain as much compatibility with NLCD 1992 as possible, there were enough differences in the classifications to confound any direct comparison of the two datasets. Taking into consideration inherent differences in source image seasonality and georegistration, mapping methodologies, classification accuracy, and map legends, it became clear that a direct post classification comparison of NLCD 1992 and NLCD 2001 would be subject to unavoidable error. Recognizing both the temptation and limitation of direct comparison of NLCD 1992 with NLCD 2001, the USGS NLCD design team initiated a research effort to devise an optimal way to compare the products. To generate the product, a multistage processing method used both NLCD products in procedures that included (1) reclassification of both eras of land cover using a decision tree classifier at Anderson Level I, (2) filtering intermediate results with confidence parameters, (
