1996 Digital Orthophotos of the Puget Sound Region

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Frequently-anticipated questions:

What does this data set describe?

Title: 1996 Digital Orthophotos of the Puget Sound Region
Abstract:
One-meter natural color orthophotography for the western, urbanized, portion of King County and portions of adjoining counties. The eastern boundary is defined by a line running north-south through the North Bend area.
Supplemental_Information:
Original data was provided by the Originator in their tiling scheme. Data was retiled to standard tiling scheme for King County.
Data is available as TIFF and JPG2 compressed versions.
TIFF format data is available only at the base tiling level - idxp7500 - defined by a rectangular grid of cells with x-y dimensions of 7500 feet.
Primary user data is provided at second tier tiling level - idxptrmbr. This tiling level references the PLSS township-range grid with tiles buffered to a minimum-bounding rectangle of the township. Imagery at this level is provided only as compressed (compression ratio = 7, near lossless) imagery in JPG2000 format.
Imagery is also available as larger area mosaics at the idxpzone level (if appropriate) and as a highly compressed entire area of interest mosaic. Both the zone and entire area mosaic, called key region, is provided only as JP2 images.
  1. How should this data set be cited?

    Group, NIES Mapping , 1996, 1996 Digital Orthophotos of the Puget Sound Region: Nies Mapping Group, Inc, Bellevue, WA.

    Online Links:

    • None

    Other_Citation_Details:
    King County maintains a portion of the full project dataset covering King County and some adjacent areas in Snohomish and Pierce Counties. The full dataset includes Seattle, and its outlying areas. It is bounded to the east by and including North Bend; to the west by and including the Puget Sound coastline, to the north by and including Maryville; and finally to the south, by Tacoma.
    Originator contract info: Nies Mapping Group, Inc 2310 130th Ave NE, Suite 100 Bellevue, WA 98005-1757 206-869-4020 (voice) 206-869-4095 (fax)

  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:
    Ending_Date:
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: Digital raster data

  6. How does the data set represent geographic features?

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

    2. What coordinate system is used to 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? (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?

    Mike Leathers
    King County GIS Center
    GIS Data Coordinator
    201 S Jackson St
    Seattle, WA 98104
    USA

    206-263-4867 (voice)

Why was the data set created?

Archival orthophotos for the western King County area.

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: 1996 (process 1 of 2)
    THE SOURCE PHOTOGRAPHY
    The color aerial photography was taken with a Zeiss RMK/A 15/23 camera with forward motion compensation and mounted in a turbo / charged Cessna 206. It was flown in June and July 1996. The altitude of the aircraft, 15,000 feet above mean ground, provided photography at a nominal scale of 1:30000.
    The film used was AGFA P200. From this film, diapositives were produced on Kodak Vericolor Print Film 4111 (ESTAR Thick Base) using an electronic auto-dodge contact printer with a color light source. Auto-dodging automatically compensates for changes in light conditions typically found between flight lines or within independent photo frames along a flight line. The quality and amount of information on these diapositives is far superior to that obtainable on paper prints. These diapositives were scanned as a part of the process in creating our digital orthophotos.

    Date: 1996 (process 2 of 2)
    CONTROL
    Control was a combination of new airborne and ground based GPS along with exitsing survey databases. The primary control in turn was densified into a secondary control network by photogrammetric and aerotriangulation methods.
    DIGITAL ELEVATION DATA
    The DEM data, which is a series of {x,y,z} points within the area, was provided by USGS from existing 1:24000 scale 7 1/2 minute quads. This data was provided so that the orthophotos could be rectified to meet the 1:20000 map scale accuracy.
    ORTHOPHOTO RECTIFICATION
    The diapositives were scanned and converted to digital images using a Zeiss/Intergraph PS-1 Linear Array scanner at a sample rate of 30 microns (846 dpi). The scanning produced a raw ground image pixel of nominally 0.9 meters in size. These digital images were oriented using the above mentioned control and rectified to remove distortions caused by variations in terrain elevation and perspective geometry. During the rectification process the image pixels were resampled using the cubic convolution algorithm to a one meter resolution. The final geo-referenced orthophotos have the same accuracy as a 1:20000 map. The reference system used for this project was the State Plane North Zone NAD 83 - 91.

  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:
Imagery is available for internal use by King County. Other interested parties should contact the Originator directly.
Use_Constraints: None

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

    Mike Leathers
    King County GIS Center
    GIS Data Coordinator
    201 S Jackson St
    Seattle, WA 98104
    USA

    206-263-4867 (voice)

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

    1996 Nies natural color orthophotography

  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: 06-Oct-2003
Metadata author:
Mike Leathers
King County GIS Center
GIS Data Coordinator
201 S Jackson St
Seattle, WA 98104
USA

206-263-4867 (voice)
mike.leathers@kingcounty.gov

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

Generated by mp version 2.9.6 on Wed Apr 10 12:31:41 2013