NatcolorXXX.tif-Emerge Natural Color Derivative Aerial Photography

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Frequently-anticipated questions:

What does this data set describe?

NatcolorXXX.tif-Emerge Natural Color Derivative Aerial Photography
Low elevation, high resolution (i.e., small ground-sample-distance (GSD)) aerial photography collected in lat spring to early fall 2000 for western King County and southwestern Snohomish County. The data has a pixel size of 2 feet and is displayed in a natural color derivative for visual analysis
The images were created by converting original 'False Color' near-infrared TIFF images to a natural color derivative. It is considered a natural color derivative rather than a true natural color product as the original data is limited to 3-bands only, omitting the blue band. An algorithm was applied to the original data to closely mimic a natural color image. The images may be accessed as individual TIFF file by tile, as a pseudo-mosaic by using the associated image catalog dbase (emerge_nat.dbf) file, where supported, or as a single MrSid mosaic (emerge_nat.sid), where supported.
Detailed photodate information is not available. A general overview at the township-level for data capture dates can interpolated from www. "<>"
  1. How should this data set be cited?

    County, King, 20010126, NatcolorXXX.tif-Emerge Natural Color Derivative Aerial Photography: King County, King County, WA.

    Online Links:

    This dataset was collected as part of a larger multispectral image acquisition effort contracted through Pacific Meridian Corporation, a subsidiary of Space Imaging Inc. The Emerge dataset component was captured and delivered to Pacific Meridian by Emerge, Inc, a aerial photography firm. Licensing and use restrictions are part of this acquisition contract. Please contact the Point of Contact for licensing restrictions.
    This is part of the following larger work.

    County, King, 2000, ESA/SAO Multispectral Image Acquisition: King County, King County, WA.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -122.4505
    East_Bounding_Coordinate: -121.6212
    North_Bounding_Coordinate: 47.9738
    South_Bounding_Coordinate: 47.1155

  3. What does it look like?

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

    Beginning_Date: May-2000
    Ending_Date: Sep-2000
    Currentness_Reference: Acquisition date

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

    Geospatial_Data_Presentation_Form: Image digital data

  6. How does the data set represent geographic features?

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

      This is a Raster data set. It contains the following raster data types:

      • Dimensions 5100 (representative) x 5100 (representative), type Pixel

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

      Grid_Coordinate_System_Name: State Plane Coordinate System
      SPCS_Zone_Identifier: Washington, North
      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
      Planar coordinates are specified in Feet

      The horizontal datum used is North American Datum of 1983.
      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?

    The imagery are stored as raster TIFF format files. They have no attribute table. Information regarding the collection parameters for the imagery may be found in the metadata for the Color Infrared version of the files as well as in the metadata for the spatial index for this dataset - idxpemer.shp

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?

    King County Dept of Natural Resources
    c/o Michael Leathers
    GIS Database Administrator
    201 S. Jackson St., Suite 700
    Seattle, Washington 98104

    206-296-3775 (voice)
    206-296-3749 (FAX)

    Hours_of_Service: 8-4:30 PST M-F

Why was the data set created?

This image dataset comprises 373 individual image tiles stored in TIFF format that can be displayed as a single seamless mosaic. The images were converted from original 'False Color" near-infrared format to a natural color derivative. The imagery, within the horizontal accuracy and resolution limitations, serves as digital backdrop imagery for GIS and cartographic display. In particular, the absolute and relative horizontal accuracy should be carefully considered when either determining coordinate positions or when applying the data relative to other spatial datasets.

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?

    The raw images were georectified by the vendor using available 10m DEM supplemented by limited GPS ground control. After delivery of the tiled images, in-house horizontal accuracy analysis indicated that the data met the contract specification for 1:10000 NMAS with a CE90 of 4m (13.1 foot accuracy). However the absolute accuracy varies significantly across the project area. In general, areas in the northern one-third of the project area exhibit greater variance from known ground control than in the balance of the project area. The error allowance in the northern one-third area approaches the CE90 limit, while the southern two-third area has an error range from under 2 feet to 7 feet. See <>

  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: Online access is restricted to King County GIS users.
King County digital data may not be reproduced or redistributed in any form or by any means without the express written authorization of the King County Dept. of Information and Administrative Services. Specific constraints apply per the licensing agreement with Space Imaging.

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

    King County
    c/o Cheryl Wilder
    700 5th Ave. , Suite 2300
    Seattle, Washington 98104

    206-263-5220 (voice)

    Hours_of_Service: 8:00-5:00 PST M-F
  2. What's the catalog number I need to order this data set?

    natcolorXXX.tif where XXX references a tile_id linked to a single polygon location in idxpemer.shp index scheme

  3. What legal disclaimers am I supposed to read?

    The King County Department of Information and Administrative Services disclaims any warranty of use of any digital product beyond that which it was designed.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 26-Jan-2001
Metadata author:
King County Department of Natural Resources
c/o Michael Leathers
GIS Database Administrator
201 S. Jackson St, Suite 700
Seattle, Washington 98104

206-296-3775 (voice)
206-296-3749 (FAX)

Hours_of_Service: 8:00-4:30 M-F
Metadata standard:

Generated by mp version 2.9.6 on Wed Apr 10 12:31:48 2013