FIGURE 1.1 The major map components of a Digital Flood Insurance Rate Map (DFIRM). Top left: the base map imagery, an orthophoto, for a floodplain map upon which familiar map planimetric elements (roads, rivers, buildings, vegetation) can be identified; top center: the digital elevation data overlaid on the orthophoto give each element in the orthoimage an accurate vertical position; top right: flood hazard data, collected and modeled by surveyors and engineers in the field, are then digitally overlaid onto the ortho- and elevation map to produce the DFIRM. This report addresses the technologies used to generate the orthoimage (base) and digital elevation data of the DFIRM. Together, we describe the imagery base map and the elevation data as the “framework data” of the DFIRM in this report. SOURCE: Adapted from Maune, 2007. Reprinted with permission from the American Society for Photogrammetry and Remote Sensing.

Answering this question must take into account the purposes of the NFIP, which is intended to enable


property owners in participating communities to purchase insurance as a protection against flood losses in exchange for State and community floodplain management regulations that reduce future flood damages. Participation in the National Flood Insurance Program is based on an agreement between communities and the Federal Government. If a community adopts and enforces a floodplain management ordinance to reduce future flood risk to new construction in floodplains, the Federal Government will make flood insurance available within the community as a financial protection against flood losses. This insurance is designed to provide an insurance alternative to disaster assistance to reduce the escalating costs of repairing damage to buildings and their contents caused by floods. (FEMA, 2002a, p. 1)



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement