Uncertainty of Forested Wetland Maps Derived from Aerial Photography

Abstract

Forested wetlands (FWs) are economically and environmentally important, so monitoring of change is done using remote sensing by several U.S. federal programs. To better understand classification and delineation uncertainties in FW maps, we assessed agreement between National Wetlands Inventory maps based on aerial photography and field determinations at over 16 000 Forest Inventory and Analysis plots. Analyses included evaluation of temporal differences and spatial uncertainty in plot locations and wetland boundaries. User's accuracy for the wetlands map was 90% for FW and 68% for nonforested wetlands. High levels of false negatives were observed, with less than 40% of field-identified wetland plots mapped as such. Epsilon band analysis indicated that if delineation of FW boundaries in the southeastern U.S. met the data quality standards (5 meters), then the area within uncertainty bounds accounts for 15% to 30% of estimated FW area.