FAIRFAX WATER FIRE HYDRANTS

Section Index

Identification_Information
Data_Quality_Information
Spatial_Data_Organization_Information
Spatial_Reference_Information
Entity_and_Attribute_Information
Distribution_Information
Metadata_Reference_Information

Identification Information

Section Index

    Citation:
      Citation Information:
        Originator: Fairfax County Government
        Publication Date: 1/1/1996
        Title: Fairfax Water Fire Hydrants
        Geospatial Data Presentation Form: map
        Publication Information:
          Publication Place: Fairfax County, Virginia, USA
          Publisher: Fairfax County Government
    Description:
      Abstract:
        This data set is points which represent the locations of Fairfax Water maintained fire hydrants. It does not contain locations of hydrants which are maintained by other water service agencies or organizations within the County.
      Purpose: Fairfax Water places the fire hydrants on the maps as part of the documentation of the water distribution system.
      Supplemental Information:
        This data set is prepared by Fairfax Water once a month and delivered to the County GIS on CD. Fairfax Water maps its water distribution system using AutoCAD Map software. The hydrant locations are exported to an ESRI shape file along with block attributes in a dBase file. At any one time, there are a couple of hundred hydrants in the data set which are not in-service yet. New water mains and fire hydrants are added to the maps as soon as the project (such as a new subdivision) gets final approval. It is usually a couple of months before the project is installed, tested, and completed for in-service use. These “not in-service yet” hydrants are not distinguishable in the data set.
    Time Period of Content:
      Time Period Information:
        Multiple Dates/Times:
          Single Date/Time:
            Calendar Date: 2002
          Single Date/Time:
            Calendar Date: 2003
      Currentness Reference: publication date
    Status:
      Progress: Complete
      Maintenance and Update Frequency: As needed
    Spatial Domain:
      Bounding Coordinates:
        West Bounding Coordinate: -77.54533008
        East Bounding Coordinate: -77.03408065
        North Bounding Coordinate: 39.0804078
        South Bounding Coordinate: 38.61389198
      Data Set G-Polygon:
        Data Set G-Polygon Outer G-Ring:
          G-Ring Point:
            G-Ring Latitude: 39.0804078
            G-Ring Longitude: -77.54533008
          G-Ring Point:
            G-Ring Latitude: 38.61389198
            G-Ring Longitude: -77.54533008
          G-Ring Point:
            G-Ring Latitude: 38.61389198
            G-Ring Longitude: -77.03408065
          G-Ring Point:
            G-Ring Latitude: 39.0804078
            G-Ring Longitude: -77.03408065
          G-Ring Point:
            G-Ring Latitude: 39.0804078
            G-Ring Longitude: -77.54533008
    Keywords:
      Theme:
        Theme Keyword Thesaurus: None
        Theme Keyword: hydrants
        Theme Keyword: fire hydrants
      Place:
        Place Keyword Thesaurus: None
        Place Keyword: Fairfax County, Virginia, USA
    Access Constraints: None.
    Use Constraints: Bear in mind, this data set contains only Fairfax Water maintained fire hydrants.
    Point of Contact:
      Contact Information:
        Contact Organization Primary:
          Contact Organization: Fairfax Water
        Contact Position: Technical Services Supervisor
        Contact Address:
          Address Type: physical address
          Address: 8560 Arlington Bv.
          City: Merrifield
          State or Province: VA
          Postal Code: 22031
          Country: USA
        Contact Voice Telephone: (703)-289-6326
        Contact TDD/TTY Telephone: 711
        Contact Facsimile Telephone: (703)-289-6382
        Hours of Service: 7:00am - 3:15pm Monday -Friday EST
    Data Set Credit: Fairfax Water, Technical Services Branch
    Native Data Set Environment:
      ESRI ArcInfo - IBM AIX - Windows SDE - LAYER NAMES:
      FCWAMGR.FIRE_HYDRANTS

Data Quality Information

Section Index

    Attribute Accuracy:
      Attribute Accuracy Report:
        Attribute data is entered as the hydrant is plotted on the map. Last and open hydrant numbers are tracked in a database. Hydrant type is taken from the hard copy source (approved site plan). Once the new project is plotted and data is entered, another mapping technician conducts a quality check of the plots and associated data.
    Logical Consistency Report:
      The hydrants are plotted on our maps as AutoCAD blocks with attributes using a special LISP routine. It is the insertion point of this block that ends up in the ESRI shape file for the hydrant location. Logical consistency is guarantied by visual inspection and automated quality control procedures.
    Completeness Report: Continually being updated. All (100%) of the Fairfax Water maintained hydrants are plotted.
    Positional Accuracy:
      Horizontal Positional Accuracy:
        Horizontal Positional Accuracy Report: Horizontal positional accuracy for the digital data is tested by visual comparison of the source (approved site plan) with the County's planimetric features in the background.
    Lineage:
      Source Information:
        Source Citation Abbreviation: APPROVED PLAN
        Source Contribution: Fill in if needed.
      Source Information:
        Source Citation Abbreviation: SCANNED PLAN
      Source Information:
        Source Citation Abbreviation: CORRELATED IMAGE
      Source Information:
        Source Citation Abbreviation: DIGITIZED DATA
      Source Information:
        Source Citation Abbreviation: ACCEPTED DATA
      Process Step:
        Process Description:
          Scan the hard copy of the approved project/subdivision site plan using a large format scanner. This produces an electronic, raster image in a TIFF format. THE CONTACT AND THE PROCESS DATE (?) IS THE SAME FOR ALL THE PROCESS STEPS IN THE DATA QUALITY INFORMATION SECTION.
        Source Used Citation Abbreviation: APPROVED PLAN
        Source Produced Citation Abbreviation: SCANNED PLAN
        Process Contact:
          Contact Information:
            Contact Organization Primary:
              Contact Organization: Fairfax Water
            Contact Position: Technical Services Supervisor
            Contact Address:
              Address Type: physical address
              Address: 8560 Arlington Bv.
              City: Merrifield
              State or Province: VA
              Postal Code: 22031
              Country: USA
            Contact Voice Telephone: (703)-289-6326
            Contact TDD/TTY Telephone: 711
            Contact Facsimile Telephone: (703)-289-6382
            Hours of Service: 7:00am - 3:15pm Monday -Friday EST
      Process Step:
        Process Description: Correlate scanned image with existing vector map. The image is inserted into the map, scaled and rotated as necessary, to align with existing planimetric features.
        Source Used Citation Abbreviation: SCANNED PLAN
        Source Produced Citation Abbreviation: CORRELATED IMAGE
      Process Step:
        Process Description: The entire new water system (not just hydrants) on the image is then traced over (heads up digitizing) using the vector tools in AutoCAD Map. Attributes are also added at this point.
        Source Used Citation Abbreviation: CORRELATED IMAGE
        Source Produced Citation Abbreviation: DIGITIZED DATA
      Process Step:
        Process Description:
          The digitized data (map objects and attribute data) is checked by another mapping technician. Any deviation from the original approved site plan will be addressed with the mapping technician that conducted the original digitizing then corrected as required.
        Source Used Citation Abbreviation: DIGITIZED DATA
        Source Produced Citation Abbreviation: ACCEPTED DATA

Spatial Data Organization Information

Section Index

    Indirect Spatial Reference: Fire Hydrants
    Direct Spatial Reference Method: Vector

Spatial Reference Information

Section Index

    Horizontal Coordinate System Definition:
      Planar:
        Planar Coordinate Information:
          Planar Coordinate Encoding Method: Coordinate Pair
          Coordinate Representation:
            Abscissa Resolution: 0.01
            Ordinate Resolution: 0.01
          Planar Distance Units: survey feet
      Geodetic Model:
        Horizontal Datum Name: North American Datum of 1983
        Ellipsoid Name: Geodetic Reference System 80
        Semi-major Axis: 6378206
        Denominator of Flattening Ratio: 294.9786982
    Vertical Coordinate System Definition:
      Altitude System Definition:
        Altitude Datum Name: National Geodetic Vertical Datum of 1929
        Altitude Distance Units: feet
        Altitude Encoding Method: Attribute values

Entity and Attribute Information

Section Index

    Detailed Description:
      Entity Type:
        Entity Type Label: FCWAMGR.FIRE_HYDRANTS
        Entity Type Definition: Point attributes
      Attribute:
        Attribute Label: ATTRIB4
        Attribute Definition: Text 254
        Attribute Domain Values:
          Unrepresentable Domain: Attribute #4. This is an unused field at this time.
      Attribute:
        Attribute Label: HYDID
        Attribute Definition: Text 254
        Attribute Domain Values:
          Unrepresentable Domain: Hydrant identification number. This is a unique number that is the key field in a Fairfax Water database.
      Attribute:
        Attribute Label: HYDNUM
        Attribute Definition: Text 254
        Attribute Domain Values:
          Unrepresentable Domain: Hydrant number. This is a sequential number used with the tax map.
      Attribute:
        Attribute Label: HYDTYPE
        Attribute Definition: Text 254
        Attribute Domain Values:
          Enumerated Domain:
            Enumerated Domain Value: blow-off
            Enumerated Domain Value Definition: Hydrant that is connected to the bottom of the water main
            Enumerated Domain Value: air-release / air release
            Enumerated Domain Value Definition: All of these types exist. Which one is correct and what does it mean?
            Enumerated Domain Value: standard
            Enumerated Domain Value Definition: Def: What does it mean?
            Enumerated Domain Value: air-release
            Enumerated Domain Value Definition: Hydrant that is connected to the top of the water main.
            Enumerated Domain Value: standard
            Enumerated Domain Value Definition: Hydrant that is connected to the side of the water main.
    Overview Description:
      Entity and Attribute Overview: This layer contains point features. Each feature includes the hydrant number, the hydrant id, and the type of hydrant.

Distribution Information

Section Index

    Custom Order Process: Any request for system wide data must be made in writing, on company letterhead, and addressed to the Fairfax Water General Manager.

Metadata Reference Information

Section Index

    Metadata Date: 7/13/2004
    Metadata Review Date: 7/19/2004
    Metadata Future Review Date: 1/1/2005
    Metadata Contact:
      Contact Information:
        Contact Organization Primary:
          Contact Organization: Fairfax County GIS and Mapping Services
        Contact Position: Database Administrator
        Contact Address:
          Address Type: mailing and physical address
          Address: 12000 Government Center Pw. Suite 117
          City: Fairfax
          State or Province: VA
          Postal Code: 22035
          Country: USA
        Contact Voice Telephone: (703)-324-2712
        Contact TDD/TTY Telephone: 711
        Contact Facsimile Telephone: (703)-324-3937
        Contact Electronic Mail Address: gis.helpq@fairfaxcounty.gov
        Hours of Service: Monday 8:00am - 4:15pm / Tuesday 9:00am - 4:15pm / Wednesday - Friday 8:00am - 4:15pm (EST)
    Metadata Standard Name: FGDC Content Standards for Digital Geospatial Metadata
    Metadata Standard Version: FGDC-STD-06-1994
    Metadata Time Convention: local time
SMMS Metadata report generated 7/19/2004