SDERaster.DBO.TX_NED_ELEV

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Frequently-anticipated questions:

What does this data set describe?

Title: SDERaster.DBO.TX_NED_ELEV
Abstract:
The U.S. Geological Survey has developed a National Elevation Dataset (NED). The NED is a seamless mosaic of best-available elevation data. The 7.5-minute elevation data for the conterminous United States are the primary initial source data. In addition to the availability of complete 7.5-minute data, efficient processing methods were developed to filter production artifacts in the existing data, convert to the NAD83 datum, edge-match, and fill slivers of missing data at quadrangle seams. One of the effects of the NED processing steps is a much-improved base of elevation data for calculating slope and hydrologic derivatives. The specifications for the NED 1 arc second and 1/3 arc second data are: Geographic coordinate system Horizontal datum of NAD83, except for AK which is NAD27 Vertical datum of NAVD88, except for AK which is NAVD29 Z units of meters.
Supplemental_Information:
The original source data set, available at <http://ned.usgs.gov>, provides additional details of the compilation of seamless Digital Elevation Model data sets.
  1. How should this data set be cited?

    REQUIRED: The name of an organization or individual that developed the data set., REQUIRED: The date when the data set is published or otherwise made available for release., SDERaster.DBO.TX_NED_ELEV.

    Online Links:

    • Service=sde:sqlserver:CHUCKNORRIS; Database=SDERaster; Version=dbo.DEFAULT

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -98.996023
    East_Bounding_Coordinate: -93.841676
    North_Bounding_Coordinate: 34.266536
    South_Bounding_Coordinate: 29.404487

  3. What does it look like?

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

    Calendar_Date: REQUIRED: The year (and optionally month, or month and day) for which the data set corresponds to the ground.
    Currentness_Reference:
    REQUIRED: The basis on which the time period of content information is determined.

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

    Geospatial_Data_Presentation_Form: vector digital data

  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):

      • G-polygon (1)
      It contains the following raster data types:
      • Dimensions 17261 x 15296 x 1, type Grid Cell

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 14
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -99.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000000
      Ordinates (y-coordinates) are specified to the nearest 0.000000
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Resolution: 1.000000
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    SDERaster.DBO.TX_NED_ELEV

    OBJECTID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Name

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Raster

    Shape.area

    Shape.len

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?

Why was the data set created?

Geospatial elevation data are utilized by the scientific and resourcemanagement communities for global change research, hydrologic modeling,resource monitoring, mapping, and visualization applications.

For use with the TRIMS project, this data set was clipped from the original dataset to contain only the Trinity River Basin study area in Texas. The elevation values were converted from meters to feet. Cell values in the layer are feet.

How was the data set created?

  1. From what previous works were the data drawn?

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

    (process 1 of 7)
    Dataset copied.

    Data sources used in this process:

    • C:\temp\tx_dems

    (process 2 of 7)
    Dataset copied.

    Data sources used in this process:

    • Y:\TFS\Slope\TX\tx_dems

    (process 3 of 7)
    Dataset copied.

    Data sources used in this process:

    • C:\kim\tx_dems

    (process 4 of 7)
    Dataset copied.

    Data sources used in this process:

    • Y:\TFS\Slope\TX\New_Work\tx_dems

    (process 5 of 7)
    Metadata imported.

    Data sources used in this process:

    • G:\test\meta\TX_DEM\tx_dems\metadata.xml

    (process 6 of 7)
    Dataset copied.

    Data sources used in this process:

    • C:\temp\demft

    (process 7 of 7)
    Metadata imported.

    Data sources used in this process:

    • P:\TRIMS\DEMs\onedem\demft\metadata.xml

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

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

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

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

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

How can someone get a copy of the data set?

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

Access_Constraints:
REQUIRED: Restrictions and legal prerequisites for accessing the data set.
Use_Constraints:
REQUIRED: Restrictions and legal prerequisites for using the data set after access is granted.

  1. Who distributes the data set?[Distributor contact information not provided.]

  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 21-Aug-2007
Metadata author:
REQUIRED: The organization responsible for the metadata information.
c/o REQUIRED: The person responsible for the metadata information.
REQUIRED: The city of the address., REQUIRED: The state or province of the address. REQUIRED: The ZIP or other postal code of the address.

REQUIRED: The telephone number by which individuals can speak to the organization or individual. (voice)

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

Generated by mp version 2.8.6 on Tue Aug 21 14:36:36 2007