Q3 Flood Data, COFFEE COUNTY, ALABAMA

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Frequently anticipated questions:


What does this data set describe?

Title: Q3 Flood Data, COFFEE COUNTY, ALABAMA
Abstract:
The Q3 Flood Data are derived from the Flood Insurance Rate Maps (FIRMs) published by the Federal Emergency Management Agency (FEMA). The file is georeferenced to the earth's surface using the Universal Transverse Mercator (UTM) projection and a zonal coordinate system (units in meters). Specifications for the horizontal control of Q3 Flood Data files are consistent with those required for mapping at a scale of 1:24000.
  1. How should this data set be cited?

    Federal Emergency Management Agency, 1996, Q3 Flood Data, COFFEE COUNTY, ALABAMA: Federal Emergency Management Agency, Washington, DC.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -86.250
    East_Bounding_Coordinate: -85.750
    North_Bounding_Coordinate: 31.750
    South_Bounding_Coordinate: 31.125

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Calendar_Date: 1996
    Currentness_Reference: Publication date

  5. What is the general form of this data set?

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Point (589)
      • String (1463)
      • GT-polygon composed of chains (590)

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: .9996
      Longitude_of_Central_Meridian: -87
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    In addition to locational and topological information, Q3 Flood Data elements are explicitly encoded using 14 MAJOR/MINOR code pairs which identify characteristics about the attribute items. Each attribute item identifies characteristics about the Flood Hazard Area, COBRA, Floodway, Political Jurisdiction, Quadrangle, or FIRM panel. All polygon data elements are encoded with fourteen feature characteristics. Number of Attributes in Entity: 28
    Entity_and_Attribute_Detail_Citation:
    The FEMA "Q3 Flood Data Specifications" contain a detailed description of each attribute code and a reference to other relevant information.
    Flood Hazard Zones
    Flood Hazard Zones are defined in Q3 Flood Data files by 28 items that describe their Flood Hazard Area, COBRA, Floodway, Political Jurisdiction, Quadrangle, or FIRM panel. (Source: FEMA FIRM, digital data sources, or other information as appropriate.)

    Flood Hazard Zones
    Data record comprising 28 fields. (Source: FEMA FIRM, digital data dources, or other information as appropriate.)

    Unknown

    MAJOR1
    3-digit Political Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    410Unknown

    MINOR1
    4-digit Political Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    Multiple codes-refer to "Q3 Flood Data Specifications"Unknown

    MAJOR2
    3-digit Political Area parameter attribute code: State FIPS (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    410Unknown

    MINOR2
    State FIPS code (Source: Federal Information Processing Standard (FIPS)-NIST)

    Frequency of measurement: Unknown

    Formal codeset
    Codeset Name:Federal Information Processing Standard (FIPS)
    Codeset Source:National Institute of Standards & Technology (NIST)

    MAJOR3
    3-digit Political Area parameter attribute code: County or Equivalent FIPS (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    411Unknown

    MINOR3
    County or equivalent FIPS code (Source: Federal Information Processing Standard (FIPS)-NIST)

    Frequency of measurement: Unknown

    Formal codeset
    Codeset Name:Federal Information Processing Standard (FIPS)
    Codeset Source:National Institute of Standards & Technology (NIST)

    MAJOR4
    3-digit Political Area parameter attribute code: Community Number (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    412Unknown

    MINOR4
    4-digit Political Area parameter attribute code Community Number (Source: FEMA FIRM,"Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    FEMA Community Identification number

    MAJOR5
    3-digit Map Panel Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    420Unknown

    MINOR5
    4-digit Map Panel Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    Multiple codes-refer to "Q3 Flood Data Specifications"Unknown

    MAJOR6
    3-digit Map Panel Area attribute parameter code: FIRM Panel Number (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    421Unknown

    MINOR6
    4-digit Map Panel Area attribute parameter code: FIRM Panel Number (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    Unique numeric sequence derived from FIRMs

    MAJOR7
    3-digit Map Panel Area attribute parameter code: FIRM Panel Alpha Character numeric equivalent (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    422Unknown

    MINOR7
    4-digit Map Panel Area attribute parameter code: FIRM Panel Alpha Character numeric equivalent (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    Range of values
    Minimum:0001 [ equivalent to "A"]
    Maximum:0026 [ equivalent to "Z"]

    MAJOR8
    3-digit USGS 7.5-minute Quadrangle Area attribute (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    420Unknown

    MINOR8
    4-digit USGS 7.5-minute Quadrangle Area attribute (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    0170Unknown

    MAJOR9
    3-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Latitude (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    426Unknown

    MINOR9
    4-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Latitude (degrees) (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    Range of values
    Minimum:+0000
    Maximum:+0090

    MAJOR10
    3-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Longitude (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    427Unknown

    MINOR10
    4-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Longitude (degrees) (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    Range of values
    Minimum:-0180
    Maximum:+0180

    MAJOR11
    3-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Identifier (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    428Unknown

    MINOR11
    4-digit USGS 7.5-minute Quadrangle Area parameter attribute code: Identifier (Source: USGS Quadrangle Index, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    Range of values
    Minimum:0011 ["A1" numeric equivalent]
    Maximum:0088 ["H8" numeric equivalent]

    MAJOR12
    3-digit Flood Hazard Zone Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    440Unknown

    MINOR12
    4-digit Flood Hazard Zone Area attribute code (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    Multiple codes-refer to "Q3 Flood Data Specifications"Unknown

    MAJOR13
    3-digit Flood Hazard Zone Area attribute code: Floodway (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    440Unknown

    MINOR13
    4-digit Flood Hazard Zone Area attribute code: Floodway (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    Multiple codes-refer to "Q3 Flood Data Specifications" documentUnknown

    MAJOR14
    3-digit Undeveloped Coastal Barrier Area attribute (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    440Unknown

    MINOR14
    4-digit Undeveloped Coastal Barrier Area attribute (Source: FEMA FIRM, "Q3 Flood Data Specifications")

    Frequency of measurement: Unknown

    ValueDefinition
    Multiple codes-refer to "Q3 Flood Data Specifications"Unknown


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

  3. To whom should users address questions about the data?

    Federal Emergency Management Agency, Mitigation Directorate
    500 C Street, S.W.
    Washington, District of Columbia 20472

    1-800-358-9616 (voice)


Why was the data set created?

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 located or to be located in identified areas having special flood hazards" (Section 2 (b) (4) of the 1973 Flood Disaster Protection Act). 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 insurance coverage offered through the NFIP. Q3 Flood Data files are intended to convey certain key features from the existing hard copy FIRM to provide users with automated flood risk data. Edge-matching errors, overlaps and deficiencies in coverage, and similar problems are not corrected during digitizing or post-processing. These data may be used to locate SFHAs. More detailed information may be obtained from the paper FIRM.


How was the data set created?

  1. From what previous works were the data drawn?

    FIRM1 (source 1 of 5)
    Federal Emergency Management Agency, 19901205, Flood Insurance Rate Map, COFFEE COUNTY (Unincorporated Areas), AL: Federal Emergency Management Agency, Washington, DC.

    Other_Citation_Details:
    Panel: 0102390000 - Source_Scale_Denominator: NA Panel: 0102390025B - Source_Scale_Denominator: 24000 Panel: 0102390050B - Source_Scale_Denominator: 24000 Panel: 0102390075B - Source_Scale_Denominator: 24000 Panel: 0102390100B - Source_Scale_Denominator: 24000 Panel: 0102390125B - Source_Scale_Denominator: 24000 Panel: 0102390150B - Source_Scale_Denominator: 24000 Panel: 0102390175B - Source_Scale_Denominator: 24000 Panel: 0102390200B - Source_Scale_Denominator: 24000
    Type_of_Source_Media: paper
    Source_Contribution: spatial and attribute information

    FIRM2 (source 2 of 5)
    Federal Emergency Management Agency, 19760507, Flood Insurance Rate Map, CITY OF ELBA, AL: Federal Emergency Management Agency, Washington, DC.

    Other_Citation_Details:
    Panel: 0150040001A - Source_Scale_Denominator: 12000 Panel: 0150040002A - Source_Scale_Denominator: 12000 Panel: 0150040003A - Source_Scale_Denominator: 12000 Panel: 0150040004A - Source_Scale_Denominator: 12000
    Type_of_Source_Media: paper
    Source_Contribution: spatial and attribute information

    FIRM3 (source 3 of 5)
    Federal Emergency Management Agency, 19800702, Flood Insurance Rate Map, CITY OF ENTERPRISE, AL: Federal Emergency Management Agency, Washington, DC.

    Other_Citation_Details:
    Panel: 0100450000 - Source_Scale_Denominator: NA Panel: 0100450002B - Source_Scale_Denominator: 6000 Panel: 0100450003B - Source_Scale_Denominator: 6000 Panel: 0100450004B - Source_Scale_Denominator: 6000 Panel: 0100450005B - Source_Scale_Denominator: 6000 Panel: 0100450006B - Source_Scale_Denominator: 6000
    Type_of_Source_Media: paper
    Source_Contribution: spatial and attribute information

    FIRM4 (source 4 of 5)
    Federal Emergency Management Agency, 19771230, Flood Insurance Rate Map, TOWN OF KINSTON, AL: Federal Emergency Management Agency, Washington, DC.

    Other_Citation_Details:
    Panel: 0102370001A - Source_Scale_Denominator: 9600 Panel: 0102370002A - Source_Scale_Denominator: 9600
    Type_of_Source_Media: paper
    Source_Contribution: spatial and attribute information

    FIRM5 (source 5 of 5)
    Federal Emergency Management Agency, 19770722, Flood Insurance Rate Map, TOWN OF NEW BROCKTON, AL: Federal Emergency Management Agency, Washington, DC.

    Other_Citation_Details:
    Panel: 0102380001A - Source_Scale_Denominator: 9600 Panel: 0102380002A - Source_Scale_Denominator: 9600
    Type_of_Source_Media: paper
    Source_Contribution: spatial and attribute information

  2. How were the data generated, processed, and modified?

    (process 1 of 1)
    Q3 Flood Data were produced by either scanning and vectorizing or manually digitizing a hardcopy version of the graphic materials. The scanning and vectorization process captured the digital data as raster data which were vectorized and attributed on an interactive editing station. The manual digitizing process used a digitizing table to capture the digital data; attribution was performed either as the data were digitized or on an interactive edit station after the digitizing was completed. The determination of the production methodology was based on various criteria, including availability of production systems. Four to nine control points per FIRM panel were used for registration during manual digitizing. A projective transformation was performed on the coordinates used in the data collection and editing systems to register the digital data to the Universal Transverse Mercator (UTM) grid coordinates. An ARC/INFO coverage of the Q3 Flood Data was generated and was used to create the Q3-DLG file. The Q3 Flood Data were checked for position and attribute accuracy by comparing plots of the digital data to the source graphic and by symbolized display on an interactive computer system. Selected attributes that could not be visually verified were individually queried. In addition, an ARC/INFO Arc Macro Language (AML) software program was applied to the dataset to test the attributes against a master set of valid attributes for the specific data category, and a complete set of valid attribute combinations. Source graphics were revised to reflect updates effected by Letters of Map Change (Letter of Map Revision [LOMR], Letter of Map Amendment [LOMA]). These revisions were included in the Q3 Flood Data if they were mappable at the publication scale of the source graphic. Once final, the ARC/INFO Coverage was projected into a geographic grid system, using decimal degree latitude and longitude coordinates, and then converted into an ARC/INFO Export file and MapInfo native tables files. In addition, the ARC/INFO coverage in UTM coordinates was converted into a Digital Line Graph file (DLG). All final files were checked for logical consistency and completeness.

  3. What similar or related data should the user be aware of?

    Federal Emergency Management Agency, 1996, Q3 Flood Data Coverage, COFFEE COUNTY, AL: Federal Emergency Management Agency, Washington, DC.

    Federal Emergency Management Agency, 1996, Q3 Raster FIRM, COFFEE COUNTY, AL: Federal Emergency Management Agency, Washington, DC.

    Federal Emergency Management Agency, 1996, EFIRM, COFFEE COUNTY, AL: Federal Emergency Management Agency, Washington, DC.


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The Q3 Flood Data are countywide vector files derived from FEMA FIRMs. The attribute definitions may be found in the "Q3 Flood Data Specifications". Attribute accuracy was tested by manual comparison of source graphic with hardcopy plots and a symbolized display on an interactive computer system. Selected attributes that could not be visually verified were individually queried. In addition, an ARC/INFO Arc Macro Language (AML) software program was applied to the dataset to test the attributes against a master set of valid attributes for the specific data category, and a complete set of valid attribute combinations. (See also Entity Attribute Information).

  2. How accurate are the geographic locations?

    Specifications for the digitizing of FIRMs to create the Q3 Flood Data are consistent with those requirements for mapping at a scale of 1:24000. Horizontal control of Q3 Flood Data was established using USGS quadrangle maps at 1:24000 or other standard scales. Users should assess the horizontal positional accuracy of the Q3 Flood Data with regard to the selected base map sources and the requirements of their application. With increased frequency, large-scale spatial data sets are becoming widely available for computer-based geographic information systems. Q3 Flood Data may be used in combination with other digital spatial data; however, users should be aware that scalar enlargements do not enhance the relative accuracy of the Q3 Flood Data.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Data completeness for Q3 Flood Data files reflect the content of the source graphic. Features may have been eliminated or generalized on the source graphic, due to scale and legibility constraints. 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 analysis 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 undeveloped 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. Q3 Flood Data may be derived from DFIRM-DLGs, from FIRM-DLGs, from FIRMs digitized previously for emergency applications, or may be newly created files. In Q3 Flood Data derived from older data sets, certain items may not have been captured or may have been captured differently from the current Q3 Flood Data specifications. In some cases, preliminary FIRM data have been included in the Q3 Flood Data files. These data have been provided to the community for their review and comment, and may be subject to change before their final publication date. In addition, in some cases, areas designated as Flood Prone Areas on maps prepared by USGS and FIA have been included in the Q3 Flood Data files. These areas were delineated based on available information on past floods, and are described by a unique attribute code that distinguishes them from areas of 1% annual chance flooding derived from FIRMs. Flood Insurance Rate Maps continually undergo revisions and updates. Some of these revisions are effected by letter (Letter of Map Revision [LOMR], Letter of Map Amendment [LOMA]). Q3 Flood Data may not reflect the most current information or information that is not mappable at the publication scale of the FIRM. To obtain the latest information, contact the address listed under distributor.

  5. How consistent are the relationships among the observations, including topology?

    Polygon and chain-node topology are present. Certain node-area-line relationships are collected or generated to satisfy topological requirements. Some of these requirements include: lines must begin and end at nodes, lines must connect to each other at nodes, lines do not extend through nodes, left and right areas are defined for each line segment and are consistent throughout the files, and the lines representing the limits of the file neatlines are free of gaps. Tests of logical consistency were performed by ARC/INFO software modules. Check plots were made to test for leaks in all internal polygons.


How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
None. Acknowledgment of FEMA would be appreciated in products derived from these data.

  1. Who distributes the data set? (Distributor 1 of 1)

    Federal Emergency Management Agency, Map Service Center
    6730 Santa Barbara Court
    Baltimore, Maryland 21227-5832

    1-800-358-9616 (voice)

    Contact_Instructions:
    Data requests should include the full name of the community or county and the Flood Insurance Rate Map panel number(s) or the 7.5-minute quadrangle sheet area(s) covered by the request.
  2. What's the catalog number I need to order this data set?

  3. What legal disclaimers am I supposed to read?

    No warranty expressed or implied is made by FEMA regarding the utility of the data on any other system nor shall the act of distribution constitute any such warranty. FEMA will warrant the delivery of this product in a computer-readable format, and will offer appropriate adjustment of credit when the product is determined unreadable by correctly adjusted computer input peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustment of credit must be made within 90 days from the date of this shipment from the ordering site.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 21-Mar-1996
Metadata author:
Federal Emergency Management Agency, Mitigation Directorate
500 C Street, S.W.
Washington, District of Columbia 20472

1-800-358-9616 (voice)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


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