Transportation
Metadata from the RGIS Metadata Repository
Identification Information
- Title Transportation
- Date 2009-08-03
- Date Type Publication
- Cited Responsible Party
-
- Organization Name Federal Emergency Management Agency
- Role identify
- Presentation Form vector digital data
- Abstract The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by
FEMA, and any Letters Of Map Revision (LOMRs) that have been issued against those databases since their publication date.
The DFIRM Database is the digital, geospatial version of the flood hazard information shown on the published paper Flood Insurance
Rate Maps(FIRMs). The primary risk classifications used are the 1-percent-annual-chance flood event, the 0.2-percent-annual-chance
flood event, and areas of minimal flood risk. The NFHL data are derived from Flood Insurance Studies (FISs), previously published
Flood Insurance Rate Maps (FIRMs), flood hazard analyses performed in support of the FISs and FIRMs, and new mapping data
where available. The FISs and FIRMs are published by the Federal Emergency Management Agency (FEMA). The specifications for
the horizontal control of DFIRM data are consistent with those required for mapping at a scale
of 1:12,000. The NFHL data contain layers in the Standard DFIRM datasets except for S_Label_Pt and S_Label_Ld. The NFHL
is available as State or US Territory data sets. Each State or Territory data set consists of all DFIRMs and corresponding
LOMRs available on the publication date of the data set.
- Purpose The FIRM is the basis for floodplain management, mitigation, and insurance activities for the National Flood Insurance Program
(NFIP). Insurance applications include enforcement of the mandatory purchase requirement of the Flood Disaster Protection
Act, which "... requires the purchase of flood insurance by property owners who are being assisted by Federal programs or
by Federally supervised, regulated or insured agencies or institutions in the acquisition or improvement of land facilities"
(Section 2 (b) (4) of the Flood Disaster Protection Act of 1973). In addition to the identification of Special Flood Hazard
Areas (SFHAs), the risk zones shown on the FIRMs are the basis for the establishment of premium rates for flood coverage offered
through the NFIP. The NFHL data present the flood risk information depicted on the FIRM in a digital format suitable for use
in electronic mapping applications. The NFHL database is a subset of the information created for the FIS
and serves as a means to archive a portion of the information collected during the FIS.
- Status In work
- Point of Contact
-
- Individual Name
- Organization Name Federal Emergency Management Agency
- Position Name
- Role Point of contact
- Voice 1-877-FEMA-MAP
- Facsimile
- Address
-
- Delivery Point 500 C Street, S.W.
- City Washington
- Administrative Area District of Columbia
- Postal Code 20472
- Country USA
- Electronic Mail Address fema-mscservice@dhs.gov
- Maintenance and Update Frequency Monthly
- Descriptive Keywords DFIRM, FIRM, FEMA Flood Hazard Zone, DFIRM Database, Special Flood Hazard Area, Digital Flood Insurance Rate Map, CBRS, Coastal
Barrier Resources System, Riverine Flooding, Coastal Flooding, NFIP, Base Flood Elevation, SFHA, Flood Insurance Rate Map,
Floodway
- Access Constraints None
- Use Constraints Acknowledgement of FEMA would be appreciated in products derived from these data.
- Language English
- Topic Category environment
- Extent
-
- Geographic Bounding Box
-
- West Bound -103.814855380274
- East Bound -103.052629499222
- North Bound 33.5705998361398
- South Bound 32.0002375254958
- Temporal Extent
-
- DateTime 2009-01-16
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Distribution Information
- Distributor
-
- Individual Name
- Organization Name Earth Data Analysis Center
- Position Name Clearinghouse Manager
- Role Point of contact
- Voice 505-277-3622 ext. 230
- Facsimile 505-277-3614
- Address
-
- Delivery Point MSC01 1110
- Delivery Point 1 University of New Mexico
- City Albuquerque
- Administrative Area NM
- Postal Code 87131-0001
- Country USA
- Electronic Mail Address clearinghouse@edac.unm.edu
- Transfer Options
-
- Online Resource ZIP
- Online Resource ESRI Shapefile (shp)
- Online Resource GML
- Online Resource KML
- Online Resource GeoJSON
- Online Resource JSON
- Online Resource Comma Separated Values (csv)
- Online Resource MS Excel format (xls)
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Spatial Reference Information
- Spatial References
-
- Spatial Reference North American Datum of 1983
-
- Online Reference EPSG:4269
- Spatial Reference Geodetic Reference System 80
-
- Online Reference EPSG:7019
- Spatial Reference Mixed
-
- Online Reference EDAC:Unknown
- Indirect Spatial Reference Eddy County (35015)
- Geometric Object Type String
- Geometric Object Count 6347
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Data Quality Information
- Attribute Accuracy Report
-
- Report The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by
FEMA, and any Letters Of Map Revision (LOMRs) that have been issued against those databases since their publication date.
The DFIRM Database consists of community based vector files and associated attributes produced in conjunction with the hard
copy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the Special Flood Hazard
Areas (SFHAs). As such they are adopted by local communities and form the basis for administration of the National Flood Insurance
Program (NFIP). For these purposes they are authoritative. Provisions exist in the regulations for public review, appeals
and corrections of the flood risk information shown to better match real world conditions. As with any engineering analysis
of this type, variation from the estimated flood heights and floodplain boundaries is possible. Details
of FEMA's requirements for the FISs and flood mapping process that produces these data are available in the Guidelines
and Specifications for Flood Hazard Mapping Partners. Attribute accuracy was tested by manual comparison of source graphics
with hardcopy plots and a symbolized display on an interactive computer graphic system. Independent quality control testing
of FEMA's DFIRM databases was also performed. To obtain more detailed information in areas where Base Flood Elevations (BFEs)
and/or floodways have been determined, users are encouraged to consult the Flood Profiles and Floodway Data and/or Summary
of Stillwater Elevations tables contained within the FIS report that accompanies the individual components of the DFIRM data.
Users should be aware that BFEs shown in the S_BFE table represent rounded whole-foot elevations. These BFEs are intended
for flood insurance rating purposes only and should not be used as the sole source of flood elevation information.
Accordingly, flood elevation data presented in the FIS report must be used in conjunction with the FIRM for purposes of
construction and/or floodplain management. The 1-percent-annual-chance water-surface elevations shown in the S_XS table match
the regulatory elevations shown in the FIS report.
- Quantitative Attribute Accuracy Assessment
-
- Attribute Accuracy Value
- Attribute Accuracy Explanation
- Horizontal Positional Accuracy Report
-
- Report The National Flood Hazard Layer data consists of community based vector files and associated attributes produced in conjunction
with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the SFHAs.
As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are
authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information
shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood
heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that
produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. Horizontal accuracy
was tested by manual comparison of source graphics with hardcopy plots and a symbolized display
on an interactive computer graphic system. Independent quality control testing of the individual DFIRM data sets was
also performed.
- Quantitative Horizontal Positional Accuracy Assessment
-
- Horizontal Positional Accuracy Value
- Horizontal Positional Accuracy Explanation
- Vertical Positional Accuracy Report
-
- Report The National Flood Hazard Layer data consists of community based vector files and associated attributes produced in conjunction
with the hardcopy FEMA FIRM. The published effective FIRM and DFIRM maps are issued as the official designation of the SFHAs.
As such they are adopted by local communities and form the basis for administration of the NFIP. For these purposes they are
authoritative. Provisions exist in the regulations for public review, appeals and corrections of the flood risk information
shown to better match real world conditions. As with any engineering analysis of this type, variation from the estimated flood
heights and floodplain boundaries is possible. Details of FEMA's requirements for the FISs and flood mapping process that
produces these data are available in the Guidelines and Specifications for Flood Hazard Mapping Partners. Vertical accuracy
was tested by manual comparison of source graphics with hardcopy plots and a symbolized display on
an interactive computer graphic system. Independent quality control testing of the individual DFIRM data sets was also
performed.
- Quantitative Vertical Positional Accuracy Assessment
-
- Vertical Positional Accuracy Value
- Vertical Positional Accuracy Explanation
- Logical Consistency Report When FEMA revises an FIS, adjacent studies are checked to ensure agreement between flood elevations at the boundaries. Likewise
flood elevations at the confluence of streams studied independently are checked to ensure agreement at the confluence. The
FIRM and the FIS are developed together and care is taken to ensure that the elevations and other features shown on the flood
profiles in the FIS agree with the information shown on the FIRM. However, the elevations as shown on the FIRM are rounded
whole-foot elevations. They must be shown so that a profile recreated from the elevations on the FIRM will match the FIS profiles
within one half of one foot.
- Completeness Report Information contained in the National Flood Hazard Layer data reflects the content of the source materials. Features may have
been eliminated or generalized on the source graphic, due to scale and legibility constraints. With new mapping, FEMA plans
to maintain full detail in the spatial data it produces. However, older information is often transferred from existing maps
where some generalization has taken place. Flood risk data are developed for communities participating in the NFIP for use
in insurance rating and for floodplain management. Flood hazard areas are determined using statistical analyses of records
of river flow, storm tides, and rainfall; information obtained through consultation with the communities; floodplain topographic
surveys; and hydrological and hydraulic analysis. Both detailed and approximate analyses are employed. Generally, detailed
analyses are used to generate flood risk data only for developed or developing areas of communities. For areas
where little or no development is expected to occur, FEMA uses approximate analyses to generate flood risk data. Typically,
only drainage areas that are greater than one square mile are studied. The National Flood Hazard Layer data reflects the most
current information available when the distribution data set was created.
- Lineage
-
- Source Information
-
- Source Citation
- Source Scale Denominator
- Type of Source Media digital tape media
- Source Time Period of Content
-
- DateTime 2009-01-16
- Source Currentness Reference Available effective DFIRMs and LOMRs issued against those DFIRMs.
- Source Citation Abbreviation NFHL
- Source Contribution Spatial and attribute information, floodplain widths, BFEs, floodplain location.
- Process Step
-
- Process Description The individual components of the National Flood Hazard Layer data are compiled in conjunction with the hardcopy FIRM and the
final FIS report. The specifics of the hydrologic and hydraulic analyses performed are detailed in the FIS reports available
for each community. The results of these studies are submitted in digital format to FEMA. These data and unrevised data from
effective FIRMs are compiled onto the base map used for DFIRM publication and checked for accuracy and compliance with FEMA
standards. As new DFIRM data sets are received the individual DFIRM layers are sewn into the nationwide layers of the NFHL.
LOMRs for the DFIRMs in the NFHL are cut directly into the NFHL data layers as they are being produced and finalized.
- Process Date 2009-01-16
- Process Time
- Process Contact
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Metadata Reference Information
- File Identifier 5b2a6731-9462-4341-bcd7-7da75ed44654
- Metadata Language English
- Hierarchy Level Dataset
- Date Stamp 2024-09-07
- Metadata Standard Name ISO 19115:2003
- Metadata Standard Version 1.0
- Metadata Contact
-
- Individual Name
- Organization Name Earth Data Analysis Center
- Position Name Clearinghouse Manager
- Role Point of contact
- Voice 505-277-3622 ext. 230
- Facsimile 505-277-3614
- Address
-
- Delivery Point MSC01 1110
- Delivery Point 1 University of New Mexico
- City Albuquerque
- Administrative Area NM
- Postal Code 87131-0001
- Country USA
- Electronic Mail Address clearinghouse@edac.unm.edu
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