DFIRMs = Digital Flood Insurance Rate Maps with digital orthophoto base maps

ABSTRACT

Digital prothophotos are aerial photographs that have been digitally processed and corrected, pixel by pixel, to remove all distortions so they have the metric properties of a map. They have no contour lines. Until displayed on a geographic information system, or a hardcopy print is made, they have no scale. This variable scale opens the door for cost-sharing among government agencies for the development and maintenance of a common photobase which is standardized and interoperable. Cost-sharing reduces the costs for all involved and accelerates the availability of digital orthophotos for everyone. This paper discusses advantages, disadvantages, and option for using DOQs as base maps for DFIRMs so as to improve the horizontal accuracy of DFIRMs and enable simple and direct horizontal determination of individual buildings as either in or out of flood hazard zones