King County Image/Raster base tiling index - idxp7500

Frequently-anticipated questions:

• What does this data set describe?
  1. How should this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  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 data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

Title: King County Image/Raster base tiling index - idxp7500

Abstract:

A spatial tiling index designed for storage of file-based image and other raster (i.e., LiDAR elevation, landcover) data sets. A regular grid with origin at 0,0 of the Washington North State Plane Coordinate System, with grid cells defined by orthogonal bounds 7500 feet long in easting and in northing. Only those cells currently involved in one of several image/raster data projects for King County and southwestern Snohomish County are labelled, though the labeling scheme can be extended.

The name of the spatial index is derived from the acronym (I)n(D)e(X) (P)olygons at the (7500) foot tile level, or idxp7500.

Cell label is a row-id cocantenated with a column-id generating a four-character identifier that uniquely identifies every cell. The row portion of the identifier is a two-character alpha code of the format aa, ab, ac.... ba, bb, etc. and the column portion is a two-digit integer value such as 01, 02, 03.... 11,12,13, etc. A composite cell identifier would be then, for example, aa01, aa02, .....ba11,ba12, etc.

Not all image and raster data is stored at the tiling level represented by this index. Data is stored at this level if full-resolution, uncompressed data would generate larger than manageable file sizes at a larger tile size.

Supplemental_Information:

This spatial index is one of three index or tiling levels used to store King County image and raster data. Each higher index level is designed to build upon the lower levels, with the same data often stored at more than one level (though at different resolutions) to meet a range of business and software requirements.

1. How should this data set be cited?

   County, King, 200307, King County Image/Raster base tiling index - idxp7500: 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

   Description_of_Geographic_Extent:

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 grid defined by this index is a regular grid that does not have any additional or indirect spatial reference.

      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

   Index cell identifier and descriptive attributes (Source: Software assigned and user indexed)

   tile_id

   Five-digit unique integer identifier for each cell (Source: User-defined)

   Unique integer

   tile_abb

   Unique alphanumeric identifier for each cell comprised of two-character alpha code defining in which spatial column the cell exists cocantenated with a two-digit numeric code defining in which spatial row the cell exists. Alpha portion is uppercase. (Source: User-defined)

   Alpha code

   tile_abblc

   Primary 'colloquial' identifier for each cell identical in value to the tile_abb, but where the alpha portion of the code is lowercase. Unique alphanumeric identifier comprised of two-character alpha code defining in which spatial column the cell exists cocantenated with a two-digit numeric code defining in which spatial row the cell exists. (Source: User-defined)

   Unique alphanumeric code

   col_abb

   Unique alpha identifier for each column, in uppercase. (Source: User-defined)

   Alpha codes beginning with AA and sequencing as AB, AC... AZ, then reinitializing as BA, BB, ... out to the current limit of the defined cells.

   col_abblc

   Unique alpha identifier of each column in lowercase. (Source: User-defined)

   Alpha codes beginning with aa and sequencing as ab, ac... az, then reinitializing as ba, bb, ... out to the current limit of the defined cells.

   col_id

   Three-digit numeric code uniquely identifying each column (Source: User-defined)

   Sequence initiallized at 101 and sequencing as value + 1.

   row_id

   Unique integer identifier for each row (Source: User-defined)

   One or two-digit integer identifier uniquely identifying each row. When cocantenated with column_abb to create tile_abb, the integer is left padded with a zero when necessary to ensure that all tile_abb always contain four characters.

   area_sqft

   Restating of system-generated area value to provide area value in square feet if shapefile is projected to different system. (Source: user-defined)

   Range of values
   Minimum:	56250000
   Maximum:	56250000

   area_sqkm

   Area of each cell in square kilometer (Source: User-defined)

   Range of values
   Minimum:	5.225
   Maximum:	5.225

   area_sqmi

   Area of each cell in square miles. (Source: User-defined)

   Range of values
   Minimum:	2.017
   Maximum:	2.017

   perim_ft

   Restating of system-generated area value to provide area value in square feet if shapefile is projected to different system. (Source: User-defined)

   Range of values
   Minimum:	30000
   Maximum:	30000

   perim_m

   Perimiter of each cell in meters (Source: User-defined)

   Range of values
   Minimum:	9144
   Maximum:	9144

   xmin

   Minimum State Plane Washington North Zone Easting (Source: User-defined)

   Integer

   ymin

   Minimum State Plane Washington North Zone Northing (Source: User-defined)

   Integer

   xmax

   Maximun State Plane Washington North Zone Easting (Source: User-defined)

   Integer

   ymax

   Maximun State Plane Washington North Zone Northing (Source: User-defined)

   Integer

   zonenw

   Defines whether cell belongs to Northwest Zone polygon of idxpzone index (Source: User-defined)

   Value	Definition
   NW	Cell belongs to Northwest Zone
   N	Cell does not belong to Zone

   zonene

   Defines whether cell belongs to Northeast Zone polygon of idxpzone index (Source: User-defined)

   Value	Definition
   NE	Cell belongs to Northeast Zone
   N	Cell does not belong to Zone

   zonene

   Defines whether cell belongs to Southeast Zone polygon of idxpzone index (Source: User-defined)

   Value	Definition
   SE	Cell belongs to Southeast Zone
   N	Cell does not belong to Zone

   zonesw

   Defines whether cell belongs to Southwest Zone polygon of idxpzone index (Source: User-defined)

   Value	Definition
   SW	Cell belongs to Southwest Zone
   N	Cell does not belong to Zone

   Entity_and_Attribute_Overview:

   All cells are identified with a several attributes that represent unique row, column and cell identifiers as well as other parameters. As the shapefile serves primarily as a spatial index, the tile_abb and tile_abblc are the primary attributes needed to correctly reference and describe the location of the cell tile.

   Entity_and_Attribute_Detail_Citation: None

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

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)
   

This index is primarily a data processing, data storage level index which allows all raster and image data stored at this level to be maintained in a common, consistent tile and naming scheme. The index also serves as a useful central reference scheme for identification of real-world locations.

This index level is useful for users of LiDAR-derived elevation data stored as TINS because TIN format data, as well as ASCII format data, are stored only at this tiling level. Imagery in native uncompressed format will also be stored only at this level.

As each cell is defined with orthogonal edges relative the Washington State Plane coordinate system, it accomodates most common pixel resolutions of multiple ground sample distance (gsd) without partial pixel effects and without zero or NULL data 'splinters'.

1. From what previous works were the data drawn?

   ESA/SAO (source 1 of 1)

   County, King, 2003, King County ESA/SAO Data Acquisition project: King County, King County, WA.

   Other_Citation_Details:

   This index was developed jointly between the King County Dept of Transportation Roads Maintenance Dept and the King County GIS Center

   Type_of_Source_Media: Not Applicable

   Source_Contribution:

   A common data storage mechanism for file-based image/raster data at highest (full) resolution.

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

   Date: (process 1 of 3)

   ArcInfo GENERATE command with FISHNET option was used to create the polygon coverage of individual cells. The coverage was converted to a shapefile. An integer row-id and integer column-id were updated for the PAT. The values from each of these items was cocatenated to produce a unique integer identifier for each cell.

   Date: 2002 (process 2 of 3)

   Microsoft Excel was used to create a master attribute spreadsheet with all other cell attributes tied to the unique integer id of each cell. The data from the spreadsheet was exported to text format and joined to the shapefile dbf in ArcView. The resulting updated shapefile was reexported to a final shapefile.

   Date: Jun-2003 (process 3 of 3)

   To accomodate generation of the Zone level tiling index, additional attributes were added to the index shapefile dbf to indicate of which zone each cell is a member.

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

1. How well have the observations been checked?

   Identifiers for each cell are sequential and unique.

2. How accurate are the geographic locations?

   The bounds of each cell were generated from State Plane easting and northing coordinate values defined from the 0,0 origin and at even 7500 increments.

3. How accurate are the heights or depths?

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

   The index currently covers the King County and southwestern Snohomish County areas currently involved in several related image/raster data acquisition projects. The extent has been buffered to encompass some adjoining areas.

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

   All cells have a label attribute

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 data base spatial index, idxp7500.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?
   • Availability in digital form:

     Data format:	ArcInfo Shapefile
     Network links:	\\gisdw\kclib\plibrary3\reference\indexes
     Media you can order:	CD-R, DVD+R (format CD: Read-only, DVD: DVD+R read-only)

   • Cost to order the data:

     Contact KCGIS Client Services <http://www.metrokc.gov/gis/services/> for cost of reproduction and delivery

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)