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<br />more detailed maps at scales ranging from 1:12,000 to 1:1200. This <br />level c f positional accuracy is consistent with the accuracy of the <br />hardcopy FIRMs. <br /> <br />Users "hould assess the horizontal positional accuracy of DFIRMs <br />with regard to the selected base map source and the requirement" of <br />the apFlication. <br /> <br />With increased frequency, highly detailed large seal" digixal <br />mapping, is becoming available. DFIRMs may also be used in combina- <br />tion with these data. Users should keep in mind that even though <br />the scale of the DFIRM map may be increased to overlay these data, <br />the accuracy of DFIRMs is not improved by scale enlargement. <br /> <br />. Data Model Integrity: Data set is topologically structured polygon data <br />with nodes at all intersections. <br /> <br />. Completeness: Flood risk data are developed for communities part:icipating <br />in the NFIP, for use in insurance rating, and for floodplain manage- <br />ment. Flood hazard areas are determined using statisti.cal analysis <br />of records of river flow I storm tides. and rainfall; informat:ion <br />obtained through consultation with the communitys: floodplain <br />topographic surveys; and hydrologic and hydraulic analys is, Both <br />detailed and approximate analyses are employed. Generally, detaUed <br />analyses are used to generate flood risk data only for developed or <br />developing areas of communities. For undeveloped areas where lit:tle <br />or no development is expected to occur, FEMA uses approximate <br />analyses to generate flood risk data, Typically only drainage areas <br />that are greater than 1 square mile are studied, <br /> <br />Flood Insurance Rate Maps continually undergo revisions and updat:es. <br />Some of these revisions are effected by letter (Letter of Map Revi- <br />sion, Letter of Map Amendment), DLG data files may not reflect the <br />most current information. To obtain the latest informat:ion, cont:act <br />the address listed below as Metadata contact. <br /> <br />. metadata Revision Date: YYYYMMDD <br /> <br />. Metadata Contact: Assistant Administrator <br />Office of Risk Assessment <br />Federal Insurance Administration <br />Federal Emergency Management Agency <br />500 CSt., S.IL <br />Washington, D,C, 20472 <br /> <br />10/93 <br /> <br />16 <br />