2009 Impervious and Impacted Surface of King County Washington

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Frequently-anticipated questions:

What does this data set describe?

Title: 2009 Impervious and Impacted Surface of King County Washington
Year 2009 Impervious/Impacted Surface data updated with ancillary vector sources and interpreted, manual, updates from 2009 imagery. See COMPLETENESS section in data quality for status of update progress. Refer to metadata for IMPSURF_2000 for all other background information on original impervious surface development.
  1. How should this data set be cited?

    County, King, 2011, 2009 Impervious and Impacted Surface of King County Washington: King County, King County, WA.

    Online Links:

    • Server=GISPROD; Service=sde:sqlserver:gisprod; Database=raster; User=LANDCOVER; Version=sde.DEFAULT

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.634970
    East_Bounding_Coordinate: -121.062943
    North_Bounding_Coordinate: 47.959432
    South_Bounding_Coordinate: 47.070854

  3. What does it look like?

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

    Beginning_Date: 2009
    Ending_Date: 2011
    Currentness_Reference: Imagery Acquisition Date

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

    Geospatial_Data_Presentation_Form: SDE raster digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Western King County, Southwestern Snohomish County, and Seattle WA
      This is a Raster data set. It contains the following raster data types:
      • Dimensions 159565 x 192146 x 1, type Pixel

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

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Standard_Parallel: 47.500000
      Standard_Parallel: 48.733333
      Longitude_of_Central_Meridian: -120.833333
      Latitude_of_Projection_Origin: 47.000000
      False_Easting: 1640416.666667
      False_Northing: 0.000000

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 2.000000
      Ordinates (y-coordinates) are specified to the nearest 2.000000
      Planar coordinates are specified in survey feet

      The horizontal datum used is D_North_American_1983_HARN.
      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.

      Explicit elevation coordinate included with horizontal coordinates
      Altitude_Resolution: 0.000010

  7. How does the data set describe geographic features?

    VAT table (Source: King County internal coding)

    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Source of data (Source: King County)

    12000 Ikonos multiband imagery
    24TRANS_NETWORK 2011 geometry standardized to 30 feet
    18City of Woodinvile 2004 building footprints
    15City of Seattle building footprints
    16drives, gravel, parking lots, pavement edge, sidewalk, buildings
    8buildings, impervious
    9buildings, impervious
    10driveways, parking, roads, buildings, sidewalk
    11buildings, pavement
    13paved edge, buildings
    15sidewalk, buildings, impervious
    16drives, gravel, parking lots, pavement edge, sidwwalk, buildings
    4building, streets, sidewalks
    3building, streets, sidewalks
    22Grid-paint and building outlines interpretation from 2007 Pictometry orthoimagery
    25Aerial Express 2009 Near Infrared Orthophotography
    2Buildings, Divways, Parking, Pavement, Sidewalk, Streets
    26streets, impervious
    27buildings, impervious
    28Grid-paint interpretation from 2009 Pictometry


    Impervious surface (Source: King County)

    1Impervious Surface

    4 digit Source Code

    The impervious/impacted surface interpretation is stored as native ArcInfo grids with VAT feature attribute table.

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?

    Victor High
    King County GIS Center
    GIS Analyist
    201 S Jackson Street
    Seattle, WA 98104

    206-263-4845 (voice)

Why was the data set created?

Provide a project-wide (King County and southwest Snohomish county) generalized interpretation of impervious and impacted surface current to 2009 for those areas completed. By exclusion, null value areas imply vegetated or water. Can to be used, within limitations of accuracy, to determine the distribution of these types of surfaces across the project area and to make first-order areal calculations.

How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: 2010 (process 1 of 4)
    The 2009 Impervious layer was rebuilt using Aerial Express 2009 Near Infra Red photography that completely replaces the DAIS data (Vashon Island) and the Emerge data. Ikons data for Eastern King County was retained for the 2009 update. The 2000 & 2008 TNET street layers are replaced with 2010-2011 TNET. The photography was mosaic from an external 2tb drive to \\Gisdw\unnamed\AE.gdb\AE_8bit using python script: \\Gisdw\unnamed\AE_Mosaic.py AE_Mosaic.py uses the text file: \\Gisdw\unnamed\tif_list8bit.txt. This is a list of the images on the external drive that were hand picked for mosaic. Due to the long process time and redundant overlaying of images, selected images were used instead of all of the images. The mosaic script copied the 16 bit 1 foot image from the external drive, resample the 16 bit image to 8 bit and 1 foot to 2 feet. Mosaic to AE_8bit. Batch file: (\\Gisimage\images\LandcovMaint\impervious\amls_python\update.bat) that runs the python script: \\Gisdw\unnamed\LandcovMaint\impervious\amls_python\AE_NDVI_Mosaic.py with arguments for township, range, x offset, and y offset for the entire AE IR area of King County. The x\y offsets are for adjusting the image position using 2009 Pictometry photography as the target geometry.
    The AE_NDVI_Mosaic.py script processes the GRID cells by subtracting band 2 from band 1, reclassifying values 15 and less to 1, values greater than 15 to 0 to produce a GRID with the township\range name with "null" as a suffix, i.e. t19r07null in the folder: \\Gisimage\images\LandcovMaint\impervious\raster
    Townships outside of the Aerial Express data extent were built using Python script: \\Gisimage\images\LandcovMaint\impervious\amls_python\create_new_raster.py
    The GRIDs are now ready for commission error editing using Arcmap, Arcscan, GRIDPAINT.
    The 2007 impervious layer was clipped to delete the area covered by AE. The values for the two TNET layers were reclassed to NoData.
    External building and impervious layers from cities Auburn, Bellevue, Bothell, Burien, Des Monies, Federal Way, Kent, Kirkland, Mercer Island, Redmond, Renton, SeaTac, Seattle, Shoreline, Tacoma, Tukwila, and Woodinville are coded with their source code, rasterized and mosaic to \\Gisdw\unnamed\AE.gdb\footprints by Python script: \\Gisimage\images\LandcovMaint\impervious\amls_python\mosaic_footprints.py
    Final mosaic of external data, TNET, and Aerial Express townships are put together using Python script: \\Gisimage\images\LandcovMaint\impervious\amls_python\ final2009_mosaic.py. A mosaic of the entire county is built as: \\gisdw\unnamed\AE.gdb\IMP_2009. IMP_2009 is copied to GISPROD_raster_maint.sde\RASTER_MAINT.GISC.IMPSURF_2009. Pyramids are then built.
    IMP_2009 is reclassified using \\Gisimage\images\LandcovMaint\impervious\remapfiles\remap_all_values.txt to IMPSURF_2009 to reclass "0" value to "NoData". Items "IMP" and "SOURCE" , SHORT INTEGER, are added by hand to IMPSURF_2009. IMP is calculated to 1 for all values. IMPSURF_2009 is joined with \\gisdw\unnamed\vat_data_lut.dbf, then SOURCE is calculated from vat_data_lut.dbf A_SOURCE, then unjoined by hand.
    Township grids are clipped from GISPROD_raster_maint.sde\RASTER_MAINT.GISC.IMPSURF_2009 using \\Gisdw\kclib\plibrary2\survey\shapes\polygon\idxptrmbr.shp in Python script: \\Gisimage\images\LandcovMaint\ImperviousToWarehouse\TownshipGridByMask.py Zone grids are clipped using Python script: \\Gisimage\images\LandcovMaint\ImperviousToWarehouse\ZoneGridByMask.py

    Date: 2010 (process 2 of 4)
    External city shapefile data was added with new source Values: Value 2, Auburn buildings dated 2010 Value 2, Auburn Driveways dated 2010 Value 2, Auburn Parking dated 2010 Value 2, Auburn Sidewalk dated 2010 Value 2, Auburn Streets dated 2010 Value 3, Bellevue buildings dated 2010 Value 4, Bothell buildings dated 2010 Value 4, Bothell streets dated 2010 Value 4, Bothell Sidewalks dated 2010 Value 5, Burien buildings dated 2010 Value 6, Des Moines buildings dated 2010 Value 7, Federal Way buildings dated 2010 Value 7, Federal Way impervious dated 2010 Value 8, Kent building outlines dated 2010 Value 8, Kent Impervious dated 2010 Value 9, Kirkland impervious dated 2010 Value 9, Kirkland buildings dated 2010 Value 10, Mercer Island Paved Driveways dated 2009 Value 10, Mercer Island Unpaved Driveway dated 2009 Value 10, Mercer Island Paved Parking dated 2009 Value 10, Mercer Island Unpaved Parking dated 2009 Value 10, Mercer Island Paved Road dated 2009 Value 10, Mercer Island Building dated 2010 Value 10, Mercer Island Sidewalk dated 2009 Value 11, Redmond Buildings dated 2010 Value 11, Redmond Pavement dated 2008 Value 12, Renton Buildings dated 2010 Value 13, SeaTac buildings dated 2010 Value 13, SeaTac Paved Edge dated 2010 Value 14, Seattle Buildings dated 2010 Value 15, Shoreline Buildings dated 2010 Value 15, Shoreline Impervious dated 2005 Value 16, Tukwila Drives dated 2010 Value 16, Tukwila Gravel dated 2010 Value 16, Tukwila Parking Lots dated 2008 Value 16, Tukwila Pavenment Edge Value 16, Tukwila Buildings dated 2010 Value 17, Tacoma Impervious dated 2008 Value 18, Woodinville buildings dated 2009 Value 22, Heads up Grid Paint and DDES heads up building digitizing using Pictometry Orthophoto dated 2007 Value 24, King County T-Net dated 2010-2011 Value 25, Aerial Express 2009 Near Infrared Orthophotography Value 26, Snohomish County Streets dated 2011 Value 26, Snohomish County Impervious dated 2011 Value 27, Lynnwood Buildings dated 2010 Value 27, Lynnwood Impervious dated 2010 Value 28, Heads Up Grid Paint using Pictometry Orthophoto dated 2009

    Date: 22-Feb-2011 (process 3 of 4)
    Metadata imported.

    Data sources used in this process:

    • J:\RasterMetadata\LandcovMaint\MetadataXml\Landcover2009ImperviousMetadata.xml

    Date: 02-Mar-2011 (process 4 of 4)
    Metadata imported.

    Data sources used in this process:

    • J:\RasterMetadata\LandcovMaint\MetadataXml\Landcover2009ImperviousMetadata.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?

    200 points were analyzed for accuracy for impervious classification: <http://www5.kingcounty.gov/sdc/raster/landcover/Impervious_point_qc_matrix_2009.htm>

  2. How accurate are the geographic locations?

  3. How accurate are the heights or depths?

    Not Applicable

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

    The 2009 update is a complete data update/replacement of the 2000 impervious layer. Datasets Emerge and DAIS data sources were deleted and replaced with Aerial Express Near Infra Red data and supplemented with external city vector data. King County's T-Net street network was also updated and replaced the 2000 datasets. The Ikons data that covers the east side of King County was retained. The entire King County area is complete including the "Bright Water" area townships of Snohomish County with some overlap in Pierce County. The current completed townships include:

    t19r06 t19r07 t19r08 t19r09 t19r10 t19r11 t19r12 t20r03 t20r04 t20r05 t20r06 t20r07 t20r08 t20r09 t20r10 t20r11 t20r12 t21r02 t21r03 t21r04 t21r05 t21r06 t21r07 t21r08 t21r09 t21r10 t21r11 t21r12 t22r02 t22r03 t22r04 t22r05 t22r06 t22r07 t22r08 t22r09 t22r10 t22r11 t23r02 t23r03 t23r04 t23r05 t23r06 t23r07 t23r08 t23r09 t23r10 t23r11 t24r03 t24r04 t24r05 t24r06 t24r07 t24r08 t24r09 t24r10 t24r11 t25r03 t25r04 t25r05 t25r06 t25r07 t25r08 t25r09 t25r10 t25r11 t25r12 t25r13 t26r03 t26r04 t26r05 t26r06 t26r07 t26r08 t26r09 t26r10 t26r11 t26r12 t26r13 t27r03 t27r04 t27r05 t27r06 t27r07 t27r08 t27r09 t28r04 t28r05

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

    The original base 2000 impervious surface layer was appended with vector data input for a 2007 update prior to additional interpretive work from 2009 imagery. The 2009 data set replaces the previous 2007 Impervious dataset due to the 2007 dataset's incompleteness. The 2007 update was not completed because of time constraints to manually update the raster dataset and the acquisition of 2009 Aerial Express Near Infra Red data. The order of the addition of the vector layers is significant in those areas where the vector layer information overlapped. The "VALUE" value associated with each vector source indicates the input order and 8bit source code. The Raster Mosaic function works so that the higher (later) appended data supersedes or covers any earlier value/source.

How can someone get a copy of the data set?

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

Online access is restricted to authenticated King County users. Others may obtain the data through KC GIS Center Client Services.
Use_Constraints: None

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

    Cheryl Wilder
    King County GIS Center
    Training Coordinator
    201 S. Jackson St, Room 706
    Seattle, WA 98104

    206-263-5220 (voice)

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

    Internal King County users can access the data through: Township-Range (idxptrmbr) products: (see "<http://www.kingcounty.gov/operations/GIS/GISData/Metadata/RasterDataConventions.aspx#Tiling>" "<\\gisdw\kclib\plibrary3\idxptrmbr\lndcov_imp_2009\>" as txxryy_imp002 (2-foot grids) Zone-level (idxpzone) mosaics: zxx_imp015, 15-foot grids resampled from 2-foot SDE raster mosaic KeyRegion mosaic "<\\gisdw\kclib\plibrary3\keyregion\landcover\>" contains reg_imp030, a grid resampled from the SDE raster mosaic to 30 foot resolution. This serves only as a general background interpretation for regional analysis and mapping applications.

  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?

Last modified: 11-Mar-2011
Metadata author:
Mike Leathers
King County GIS Center
GIS Data Coordinator
201 S Jackson St
Seattle, WA 98104

206-253-4867 (voice)

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

Generated by mp version 2.9.6 on Wed Apr 10 12:34:11 2013