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<br />. <br /> <br />. <br /> <br />. <br /> <br />of known location, and one or more roving receivers taking GPS measurements at unknown <br />locations. <br /> <br />Digital Data-Data displayed, recorded, or stored in binary notation. <br /> <br />Digital Elevation Model (DEM)-A file with terrain elevations recorded for the intersection <br />of a fine-grained grid and organized by quadrangle as the digital equivalent of the elevation <br />data on a topographic base map. <br /> <br />Digital Flood Insurance Rate Map (DFIRM)-A Flood Insurance Rate Map that has been <br />prepared as a digital product, which may involve converting an existing manually produced <br />FIRM to digital format, or creating a product from new digital data sources using a <br />Geographic Information System environment. The DFIRM product allows for the creation of <br />interactive, multi-hazard digital maps. Linkages are built into an associated database to allow <br />users options to access the engineering backup material used to develop the DFIRM, such as <br />hydrologic and hydraulic models, Flood Profiles, data tables, Digital Elevation Models, and <br />structure-specific data, such as digital elevation certificates and digital photographs of bridges <br />and culverts. <br /> <br />Digital Flood Insurance Rate Map-Digital Line Graph (DFIRM-DLG)-The product <br />created by extracting the flood risk thematic data from the DFIRM. The format of this <br />product is the U.S. Geological Survey Digital Line Graph Level 3 optional format, The <br />DFIRM-DLG does not include base map information, or graphic data required to create a <br />FIRM in hardcopy format, The DFIRM-DLG is intended to be the primary means of <br />transferring flood risk data depicted by FIRMs to Geographic Information Systems through a <br />public domain data exchange format. The DFIRM-DLGs are tiled the to U.S. Geological <br />Survey 1:24,000 scale topographic map series. <br /> <br />Digital Flood Insurance Rate Map (DFIRM) Spatial Database-A database designed to <br />facilitate collecting, storing, processing, and accessing data developed by FEMA, enabling <br />Mapping Partners to share the data necessary for the DFIRM production and conversion <br />process. Where possible, all mapping and engineering data elements are linked to physical <br />geographic features and georeferenced. The use of a Geographic Information System as a <br />component of the DFIRM spatial database provides the ability to georeference and overlay the <br />mapping and engineering data, allowing the database to support a wide variety of existing and <br />forthcoming FEMA engineering and mapping products. <br /> <br />Digital Line Graph (DLG)-A computer file format for mapping data that provides a <br />topological structure to describe points, lines, and polygons. FEMA has adopted the U.S, <br />Geological Survey (USGS) Digital Line Graph Level 3 optional format for National Flood <br />Insurance Program mapping and engineer requirements. A DLG may contain lists of point <br />coordinates describing boundaries, drainage lines, transportation routes, and other linear <br />features, which are organized by USGS quadrangle areas. These data are the digital <br />equivalent of the linear hydrographic and cultural data on a topographic base map. The flood <br />risk thematic layers developed by FEMA will fit the quadrangle as an overlay. <br /> <br /> <br />1ERMS-8 <br /> <br />CTpCao[J('ratlflf/ <br />Te(flJ1rcal <br />Pr1rtIH'rs <br />