King County Image/Raster DataSet Extents - allextents.shp and individual extent shapefiles

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Frequently-anticipated questions:


What does this data set describe?

    Title:
    King County Image/Raster DataSet Extents - allextents.shp and individual extent shapefiles
    Abstract:
    Geographic extent of each image/raster data set in the King County Spatial Data Warehouse, KCSDW, described as a bounding polygon. The individual polygon bounds are stored separately as x_'dataset-name'.shp and also as a composite (merged) shapefile of all overlapping bounds. The polygon bounds describe the true edge of valid data of each dataset, which may lie inside the extent of NULL or zero values, or the extent of the minimal-bounding rectangle (mbr) of the dataset.

    Many of the bounding polygons names in the merged file and the names of the individual files complement names of data subdirectories within the idxp7500 and idxptrmbr master directories, as the full extent of these datasets is comprised of multiple tiles of more limited extent. Other bounding extent titles will not have a subdirectory for the dataset as they exist solely as a single theme at the KeyRegion (maximum extent) level.

    Supplemental_Information: None

  1. How should this data set be cited?

    County, King, 200307, King County Image/Raster DataSet Extents - allextents.shp and individual extent shapefiles: King County, King County, WA.

    Online Links:

    • None

    Other_Citation_Details: None

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -121.500000
    East_Bounding_Coordinate: -121.100000
    North_Bounding_Coordinate: +47.800000
    South_Bounding_Coordinate: +47.100000

  3. What does it look like?

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

    Beginning_Date: Jan-2003
    Ending_Date: Jul-2003
    Currentness_Reference: Publication date

  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?

      Indirect_Spatial_Reference:
      The polygon bounds of each shapefile describe the extent of valid data for that raster dataset. No other spatial reference is implied.
      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • Ring composed of arcs

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

      Grid_Coordinate_System_Name: State Plane Coordinate System 1983
      State_Plane_Coordinate_System:
      SPCS_Zone_Identifier: Washington, North
      Lambert_Conformal_Conic:
      Standard_Parallel: 47.500000
      Standard_Parallel: 48.733333
      Longitude_of_Central_Meridian: -120.833333
      Latitude_of_Projection_Origin: 47.000000
      False_Easting: 1640416.666500
      False_Northing: 0.000000

      Planar coordinates are encoded using Row and column
      Abscissae (x-coordinates) are specified to the nearest 1
      Ordinates (y-coordinates) are specified to the nearest 1
      Planar coordinates are specified in Survey feet

      The horizontal datum used is North American Datum of 1983, 1991 Adjustment (HPGN).
      The ellipsoid used is GRS 80.
      The semi-major axis of the ellipsoid used is 20925604.4720406.
      The flattening of the ellipsoid used is 1/298.26.

  7. How does the data set describe geographic features?

    Shapefile dbf attribute file
    Polygon identifier and descriptive attributes (Source: Software assigned and user indexed)

    id
    Sequential identifier by dataset group (Source: User-defined)

    four-digit integer

    abbrev
    Short-phrase description of dataset name (Source: User-defined)

    alphanumeric

    name
    Full name of raster/image data set (Source: User-defined)

    alphanumeric

    desc
    General summary description of the dataset and its derivative products (Source: User-defined)

    alphanumeric

    Entity_and_Attribute_Overview:
    Each polygon is provided with descriptive attributes to allow on-inspection identification of the dataset to which it refers. The description in the 'desc' item is not meant as a substitute for the data set metadata.

    Entity_and_Attribute_Detail_Citation: None


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?

    Michael Leathers
    King County Geographic Information Center,
    GIS Data Coordinator
    201 S Jackson St, Suite 706
    Seattle, WA 98104
    USA

    206-263-4867 (voice)


Why was the data set created?

Few of the raster data sets in the KCSDW have coincident extents so the extents polygons can be used to determine if valid data from that dataset exists for a given area of interest.

These extent polygons are not tiling or spatial indexes as they do not indicate how the data is subdivided and stored in the warehouse. Users are refered to the tiling indexes and associated metadata available on the KCGIS Spatial Data Catalog webpage at

<http://www.metrokc.gov/gis/sdc/index.htm>

This theme may be used in conjunction with the raster status indexes, raststat_7500.shp and raststat_trmbr.shp, which illustrate the availability of tiles in the raster library. The status indexes will show if a tile exists for a given dataset but the extent theme is required to determine if the full extent of a given tile contains valid data, i.e, useable imagery, elevation grid, landcover data.


How was the data set created?

  1. From what previous works were the data drawn?

    KCSDW (source 1 of 1)
    County, King, 2003, Various King County Spatial Data Warehouse Image/Raster datasets: King County, King County, WA.

    Other_Citation_Details: None
    Type_of_Source_Media: Raster digital data
    Source_Contribution: Raster/Imagery extents

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

    Date: (process 1 of 2)
    Heads up digitizing was used to create and edit vectors defining the bounds of each raster data set.

    Date: (process 2 of 2)
    Shapefiles were created from each dataset's digitized bounds. Four attribute items were added and populated for each shapefile. The shapefiles were merged in ArcView 3.2a using the GeoProcessing Extension. The individual shapefiles are preserved for use as individual shapefiles or for conversion to coverages. As new datasets are acquired, a new extents polygon will be generated and all the individual polygons can be merged into a replacement file.

  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?

    Description of the data set whose bounding polygon is illustrated is based on a general summary of the different versions and formats of image and/or other raster data derived from that data set. It is not meant to be an explicit listing of the data formats or file types available for that extent.

  2. How accurate are the geographic locations?

    The bounds of each polygon were digitized using heads-up editing of the actual imagery or raster data. Polygon bounds are estimated to be plus/minus 20 feet of acutal data extent.

  3. How accurate are the heights or depths?

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

    The polygons are manually updated as necessary to reflect the extent of all raster/image datasets stored within the KCSDW.

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

    All polygons have an integer identifier, dataset abbreviation, dataset name and general description.


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

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

    Dennis Higgins
    King County GIS Center, Client Services,
    Manager, Client Services Division
    201 S Jackson St, Suite 706
    Seattle, WA 98104
    USA

    206-263-4523 (voice)

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

    Image/Raster dataset extents, allextent.shp and separate shapefile extents identified as x_'dataset-name'.shp

  3. What legal disclaimers am I supposed to read?

    King County disclaims any warranty of use of any digital product or data beyond that for which it was designed.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 15-Jul-2003

Metadata author:
Michael Leathers
King County GIS Center,
GIS Data Coordinator
201 S Jackson St, Suite 706
Seattle, WA 98104
USA

206-263-4863 (voice)
mike.leathers@metrokc.gov

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


Generated by mp version 2.7.33 on Sat Dec 18 22:13:00 2004