Comparing Digital Flood Insurance Rate Maps (DFIRMs) to Interferometric Synthetic Aperture Radar (IFSAR) Products

As part of the Federal Emergency Management Agency FEMA Map Modernization program, Flood Insurance Rate Maps FIRMs are converted from hard copy products to Digital Flood Insurance Rate Maps DFIRMs. The next generation of DFIRMs will have more data and better accuracy than the hard copy FIRMs. FEMAs main goal is to have the ability to update DFIRMs using Geographic Information System GIS as humans change their physical and manmade environments. This means flood models will accurately reflect the natural and manmade environments. This study investigates the accuracy of several layers of the DFIRMs for the Virginia Beach, VA, area using Interferometric Synthetic Aperture Radar IFSAR products. IFSAR Digital Elevation Model DEM and Ortho-Rectified Image ORI, referred to as a magnitude image, were used to compare the data accuracy and content of the DFIRMs. This study will provide timely information needed for future DFIRM production.