Identification_Information:
  Citation:
    Citation_Information:
      Originator: StratMap
      Publication_Date: 19990407
      Title: Hypsography 1:24,000
      Series Information:
        Series Name: Texas Elevation Framework (hypsography)
        Issue Identification: First generation statewide coverage
      Publication_Information:
        Publication_Place: Austin, TX
        Publisher: Texas Natural Resources Information System
  Description:
    Abstract:
      Hypsography (elevation contours) Digital Line Graph (DLG-3) data are
      currently derived by digitizing map features as line graph
      elements from the cartographic source materials.  The scale of the
      source materials is 1:24,000.
      The scale is also reflected in the resolution field, which states the
      ground length in meters of the smallest data collection unit (0.001
      inch) for each scale (0.610 meters for 1:24,000 scale source data).
      Large-scale Hypsography data files are derived primarily from USGS
      topographic maps published as 7.5-minute quadrangles at 1:24,000 or
      1:25,000.  The Hypsography DLG-3 has topographic relief
      (primarily contour data) and supplementary spot elevations.
      The formal and abbreviated forms of this DLG category/
      overlay are Hypsography and HP respectively.  All data structuring
      standards (topology, elements, etc.), specifications (coordinate
      systems, cell size, error definition), data quality (positional/
      attribute accuracy, edge matching, edge alignment/status), and
      distribution format information pertaining to the Hypsography DLG-3
      is provided in the National Mapping Program Geospatial Standards
      (Standards for Digital Line Graphs (Level 3)), Parts 1 - 3; 7/98
      (see http://rmmcweb.cr.usgs.gov/public/nmpstds/dlgstds.html).  All
      DLG-3 files submitted as final deliverables under this agreement
      are quality verified (per USGS DLG-3 standards) through the current
      release of the PROSIX software.

      The DLG file structure is designed to accommodate all categories of
      spatial data represented on a conventional line map. Node, line, and
      area types are accepted. The attribute coding scheme is designed
      to accommodate several basic cartographic data categories such as
      in this case, hypsography.

      Hypsography quadrangles were post-processed to include only the arcs that
      actually reflect contour information. Arcs around the borders of quads
      and those with a Major1 code of 0, -99999, or null were selected out and
      deleted from the completed StratMap product from Titan Systems Corp.  Lastly,
      quadrangles were packaged by converting first to ArcInfo coverages and
      then to arc export files with metadata in a WinZip file. All collection,
      attribution, and QA/QC tasks were performed on the data DLG format.
      All information contained in the original DLGs is kept through the
      conversion to the ArcInfo formats.

    Purpose:
      The DLG described in this document has been produced for use in a
      statewide base map series for the State of Texas.
      This metadata document describes a Hypsography digital line graph
      (DGL-3) file produced by Titan Systems Corp. of
      Portland, OR for the Texas Strategic Mapping Program (StratMap).
      StratMap is administered by the Texas Water Development Board
      (TWDB) and managed by its Texas Natural Resources Information System
      (TNRIS) division. StratMap was created to produce seven digital
      base map layers for Texas. StratMap is supported by contributions
      from the federal government, the State of Texas, and local and regional
      organizations.  The DLG products produced for StratMap and the Texas
      Water Development Board under the Texas StratMap Program reside
      in the public domain.  As described by USGS's Standards for Digital
      Line Graphs, a digital line graph is a vector file of large-scale data
      primarily from 1:24,000 scale USGS topographic quadrangles.

    Supplemental Information: Note that contours and elevation points are
      marked in both feet and meter units depending on the original
      USGS quad labeling.

  Time_Period_of_Content:
    Time_Period_Information:
      Calendar date: 20010101
    Currentness_Reference: 19990407
  Status:
    Progress: Complete
    Maintenance_and_Update_Frequency: Irregular
  Spatial_Domain:
    Bounding_Coordinates:
      West_Bounding_Coordinate: 
      East_Bounding_Coordinate: 
      North_Bounding_Coordinate:
      South_Bounding_Coordinate:
  Keywords:
    Theme:
      Theme_Keyword_Thesaurus: None
      Theme_Keyword: Digital Line Graph
      Theme_Keyword: DLG
      Theme_Keyword: DLG-3
      Theme_Keyword: 7.5 X 7.5-minute USGS quadrangle
      Theme_Keyword: Hypsography
      Theme_Keyword: Elevation
      Theme_Keyword: Contour
      Theme_Keyword: Topography
    Place:
      Place_Keyword_Thesaurus: None
      Place_Keyword: Texas
      Place_Keyword: TX
      Place_Keyword:
  Access_Constraints: None
  Use_Constraints: None.  StratMap does not warrant this data for any particular
    use and is not responsible for any damages resulting from the use of the
    data. Acknowledgement of the StratMap program and Titan Systems Corp. 
    is appreciated in products derived and use from these data.
  Point_of_Contact:
    Contact_Information:
      Contact_Organization_Primary: GeoSpatial Data Quality Analyst
        Contact_Organization: Texas Natural Resources Information System
      Contact_Address:
        Address_Type: Mailing address
        Address: 1700 N. Congress Ave., PO Box 13231
        City: Austin
        State_or_Province: TX
        Postal_Code: 78711-3231
        Country: USA
      Contact_Voice_Telephone: 512-463-8337
      Hours_of_Service: 0800 - 1700 Monday-Friday CST
      Contact_Instructions: also at http://www.tnris.org
  Data_Set_Credit: Titan Systems Corp.  Portland, OR, USGS

Data_Quality_Information:
  Attribute_Accuracy:
    Attribute_Accuracy_Report:
      DLG data represent the source graphic and, therefore, data for a given
      category will contain attribute codes that reflect the information 
      portrayed on the source.  All attribute codes of DLG data in the NDCDB
      will agree within 98.5% to attribute codes as described in Part 3 of the
      National Mapping Program Geospatial Standards (Standards for Digital 
      Line Graphs (Level 3)), Parts 1-3; 7/98 (see
      http://rmmcweb.cr.usgs.gov/public/nmpstds/dlgstds.html).  Many features
      are uniquely described by a single attribute code.  Some elements may be
      unattributed.  Each attribute code identifies the general data category
      to which a feature belongs, as well as the specific nature of the
      feature.  Codes also provide additional descriptive information.
      Attributes are needed to describe a feature, their ordering is
      significant only if ordering is necessary to indicate a relationship
      between two codes and avoid ambiguity.

  Logical_Consistency_Report:
    The topological structure of each DLG file is fully validated by
    software (PROSIX 3.9.4).  There are no extraneous intersections;
    that is, a line does not join another line or cross another line,
    except at a node.  No line extends through a node.  Polygon (area)
    adjacency is also validated; that is, area left and right topology of
    lines is consistent throughout the file.  The neatline and data limit
    line are free of gaps.  Correct application of the attribute codes is
    checked using a combination of automated and manual techniques.  PROSIX
    software is used to check code validity and application of codes.
    Manual checks, including comparison with proof plots, are used to
    confirm attribute application.  Edgematching between maps is done
    interactively using LT4X software and then verified with PROSIX.

  Completeness_Report:
    The data are collected and processed using equipment with a resolution of
    one one-thousandth inch.  The positional accuracy of the data and 
    completeness of the file are checked by visually comparing proof plots
    with the source materials.

  Positional_Accuracy:
    Horizontal_Positional_Accuracy:
      Horizontal_Positional_Accuracy_Report:
        The DLG positional error shall be less than or equal to 0.003 inches
        standard error in both x and y component directions.  The data is
        collected and processed using equipment with a resolution of 0.001 inch.
        The positional accuracy of the data and completeness of the file are
        checked by visually comparing proof plots with the source materials.
        As set by the National Map Accuracy Standards, an acceptable
        registration RMSE must be below 20 ground feet for a 1:24,000 scale map.
      Quantitative_Horizontal_Positional_Accuracy_Assessment:
        Horizontal_Positional_Accuracy_Value: 12.2
        Horizontal_Positional_Accuracy_Explanation:
          DLG positional accuracy is based on the use of standard USGS graphic
          products as the fundamental source for initial loading of the NDCDB.
          These source graphics are normally compiled to meet National Map
          Accuracy Standards, where 90% of well-defined features are to be
          within 0.02 inches of true mapped ground position (12.2 meters)
          for 1:24,000 scale source maps).  U.S. Bureau of the Budget, 1947,
          United States National Map Accuracy Standard.

  Lineage:
    Source_Information:
      Source_Citation:
        Citation_Information:
          Originator: United States Geological Survey
          Publication_Date: 
          Title: USGS 7.5 minute quadrangle map
          Publication_Information:
            Publication_Place: Denver, CO
            Publisher: United States Geological Survey
      Source_Scale_Denominator: 24,000
      Type_of_Source_Media: monochrome feature mylar separates
      Source_Time_Period_of_Content:
        Time_Period_Information:
          Single_Date/Time:
            Calendar_Date: 
        Source_Currentness_Reference:
      Source_Citation_Abbreviation: quad
      Source_Contribution: Standard USGS topographic map

    Process_Step:
      Process_Description:
        Scanning - The Eagle Anatech 4080 black and white
        production scanner is calibrated to optimize the results
        for the USGS film separates being scanned.  A scan resolution of
        800 dpi is used for all StratMap DLG separates.  Pre-processing of
        quads is performed prior to actual production processing.  In this
        manner, Titan Systems Corp. ensures that all scan files are of optimum quality 
        for production.  Batch processing is then performed on the scan
        files to prepare them for production use.  Upon completion of the
        batch processing, a visual quality check is made on the batched
        maps.  Each batched map is opened in the LT4X editing software and
        checked for presence of tics, content, and overall quality.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Registration - Next, the scanned maps are each geodetically
        registered.  RMSE values are automatically calculated in LT4X and
        this value is checked to verify map registration accuracy.  The RMSE
        is required to be within National Map Accuracy Standards.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        First Edit - The first step within the editing phase is to update
        the DLG header items to accurately reflect information found on the 
        source data.  Vector editing is then performed utilizing pre-
        established menus containing approved LT4X processing macros for
        efficient production.  Geodetic neatlines are generated in LT4X;
        these reflect the map units and projection.  The vector data will 
        then be more thoroughly cleaned in LT4X by stepping through the
        digital data on screen in a zoomed view mode.  Once vector editing 
        is complete, contours are then attributed with elevation values.
        Adjacent maps are closely reviewed during the attributing activity,
        as it is often very difficult to determine whether elevations are
        rising or falling near the neatline.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Spot Elevations - Once the Hypsography layer is complete through the
        first edit phase, corresponding spot, or point, elevations
        are then captured.  Spot elevations are collected using a digitizing
        tablet.  Published maps are registered to the tablet and spot
        elevations manually digitized.  Once spot collection is complete, a
        series of topological checks is then performed to check the
        integrity of the map.  A paper quality control plot of the spot 
        elevations is created and a visual inspection of placement and
        accuracy performed.  If errors are noticed in the spot inspection,
        they are corrected before completing the first edit.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Second Edit - The first edit soft copy and hard copy products
        are then reviewed within a controlled QA/QC process to ensure
        accuracy before finalizing data for edge matching and final PROSIX
        validation.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Edge Matching - Following the second edit step, all the adjacent
        edges are matched using LT4X.  Adjacent map files are displayed
        in an on-screen view mode, checking each edge and manipulating
        lines to match in accordance with DLG product specifications.  The
        USGS allows a six pixel movement for edge matching.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        PROSIX - The PROSIX processing is used to ensure final verification
        and for structuring purposes.  The PROSIX software structures the 
        DLG into a DCF (Digital Cartographic File), which then in turn
        can be read by PROSIX and TRMPLT.  PROSIX is also used verify
        the attributes of a single DCF, and to edgematch several DCFs before
        exporting as final DLGs.  All edge QC flags will be properly set
        in the header prior to delivery.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Final QC / Header Check - Following the final PROSIX verification
        and edgematching, a final hard copy plot is produced and then
        compared to the published map.  The plot is checked for completeness
        and accuracy.  All final DLG products delivered will meet or exceed
        accuracy guidelines established by National Mapping Program
        Technical Instructions STANDARDS FOR DIGITAL LINE GRAPHS (4/96).
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Conversion to ArcInfo coverage and export format - Following the final
        QC / Header check, the data are imported into a coverage using ArcInfo
        version 7.2 software through the dlgarc command. Topology is rebuilt
        for lines and polygons and the coverage is converted to ArcInfo export
        format (*.e00 file extension) for ease in data transfer and
        distribution.
      Process_Date: unknown

    Process_Step:
      Process_Description:
        Hypsography quadrangles were post-processed to include only the arcs
        that actually reflect contour information. Arcs around the borders of
        quads and those with a Major1 code of 0, -99999, or null were selected
        out and deleted from the completed StratMap product from Titan Systems Corp. 
	  Again, using an ArcInfo AML, the structure of the info tables was 
	  standarized prior to loading into a single spatial database layer.
	  The standards were based on discussions with USGS staff. It was decided
	  that Hypsography DLG codes were not useful past the Major6/Minor6 pair.
	  Therefore, for quadrangles with fewer than 6 major/minor pairs, fields 
	  were added to bring them up to the standard. While quadrangles with 
	  more than 6 Major/Minor pairs were trimmed down to the standard.
	  Where fields were added, values for features were set to Null (-99999).
        Lastly, quadrangles were packaged by converting first to ArcInfo
        coverages and then to arc export files with metadata in a WinZip file.
      Process_Date: 20010901

    Process_Step:
      Process_Description:
        The entire state was loaded into a single SDE layer.  By using a series of 
        SQL queries, the Major/Minor pairs were then translated into a feature 
        code/description from the original DLG codes.  The new codes are more 
        intelligible at first glance than the previous code scheme.
      Process_Date: 20031231

    Process_Step:
      Process_Description:
        Exported the contours from ArcSDE to ESRI Shapefile or 9x Personal Geodatabase.
      Process_Date: 20050228

Spatial_Data_Organization_Information:
  Direct_Spatial_Reference_Method: vector
    Point_and_Vector_Object_Information:
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: node, planar graph
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: complete chain
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains
      SDTS_Terms_Description:
        SDTS_Point_and_Vector_Object_Type: Universe polygon composed of chains

Spatial_Reference_Information:
    Horizontal_Coordinate_System_Definition: Geographic
        Latitude_Resolution:
        Longitude_Resolution:
        Geographic_Coordinate_Units: Decimal Degrees
      Geodetic_Model:
        Horizontal_Datum_Name: North American Datum of 1983
        Ellipsoid_Name: GRS1980
        Semi-major_Axis: 6378137
        Denominator_of_Flattening_Ratio: 298.25722

Entity_and_Attribute_Information:
  Overview_Description:
    Entity_and_Attribute_Overview: USGS standards for Digital Line Graphs,
       part 3. Attribute coding
    Entity_and_Attribute_Detail_Citation:
      http://rmmcweb.cr.usgs.gov/public/nmpstds/dlgstds.html

Distribution_Information:
  Distributor:
    Contact_Information:
      Contact_Organization_Primary: GeoSpatial Data Quality Analyst
        Contact_Organization: Texas Natural Resources Information System
      Contact_Address:
        Address_Type: Mailing address
        Address: 1700 N. Congress Avenue, PO Box 13231
        City: Austin
        State_or_Province: TX
        Postal_Code: 78711-3231
        Country: USA
      Contact_Voice_Telephone: 512-463-8337
        Hours_of_Service: 0800-1700 Monday-Friday CST
        Contact_Instructions: www.stratmap.org and www.tnris.org

  Resource_Description: elevation contour Digital Line Graph (Hypsography)

  Distribution_Liability:
    No warranty expressed or implied is made by Titan Systems Corp. or the State of
    Texas regarding the utility of the data on any system, nor shall the act
    of distribution constitute any such warranty.

  Standard_Order_Process:
    Digital_Form:
      Digital_Transfer_Information:
        Format_Name: ESRI Shapefile or 9.x Personal GeoDatabase
        Format_Version_Number: unknown
        Format_Specification:
        Format_Information_Content: ESRI Shapefile or 9.x Personal GeoDatabase 
      Digital_Transfer_Option:
        Online_Option:
          Computer_Contact_Information:
            Network_Address:
              Network_Resource_Name: www.tnris.org
        Offline_Option:
          Offline_Media: CD-ROM or DVD-ROM
          Recording_Format: ISO 9660
          Compatibility_information: This CD-ROM or DVD-ROM can be used with all computer
            operating systems that support CD-ROM or DVD-ROM as a storage device.
    Fees: none for download; call for current pricing on other orders.
    Ordering_Instructions: contact Texas Natural Resources Information System.
      Alternate contacts are: USGS (http://edcwww.cr.usgs.gov/glis/glis.html)
      
Metadata_Reference_Information:
  Metadata_Date: 19990407
  Metadata_Review_Date: unknown
  Metadata_Contact: Texas Natural Resources Information System
    Contact_Information:
      Contact_Organization_Primary:
        Contact_Organization: Texas Natural Resources Information System
        Contact_Person: GeoSpatial Data Quality Analyst
      Contact_Address:
        Address_Type: Mailing address
        Address: 1700 N. Congress Avenue, PO Box 13231
        City: Austin
        State_or_Province: TX
        Postal_Code: 78711-3231
        Country: USA
      Contact_Voice_Telephone: 512-463-8337
      Contact_Facsimile_Telephone: 512-463-7274
      Contact_Electronic_Mail_Address: data@tnris.state.tx.us

  Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
  Metadata_Standard_Version: FGDC-STD-001-1998
