2007 King County (Pictometry) Orthoimagery - 6 in (west) and 1 ft (east)

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:

2007 King County (Pictometry) Orthoimagery - 6 in (west) and 1 ft (east)

Abstract:

Draft 1 version 2007 (July) King County Natural Color orthoimagery acquired by Pictometry for internal business and agency use only. Pixel resolution is 1.0 foot GSD in rural (east) King County and 0.5 foot GSD in urbanized (west) King County. Higher resolution data includes portion of southwestern Snohomish County, and for the Highway 2 corridor in northeast King County and for the Apenal area near Snoqualmie Pass. The 1.0 foot data is also known as Neighborhood-level imagery whereas the 0.5 foot data is known as Community-level imagery.

Supplemental_Information:

The orthoimagery described in this metadata will be delivered in King Countys standard tiling scheme and can be viewed with existing GIS and image viewing software. The proprietary package of oblique/orthogonal imagery from Pictometry is viewable only through their ArcGIS 9.x extension and their stand-alone EFS software. Though the imagery is stored in native resolution (both 0.5 foot and 1.0 foot) in Plibrary3, ArcGIS LYR files are standardized to a naming convention of txxryy_07n050.lyr, even for areas where the GSD of the native imagery is 1 foot. ArcGIS users are encouraged to use the the Plibrary LYR files as they have been symbolized to minimize the effect of the black (0,0,0) mask along the edges of all tiles. ArcView 3.x users cannot use LYR files and must access the Plibrary3 township tiles directly. These tiles will show the black mask which will overlay valid data in adjacent tiles depending on the drawing order. Final version of this data will not have this affect.

1. How should this data set be cited?

   Pictometry (under contract with King County), 200802, 2007 King County (Pictometry) Orthoimagery - 6 in (west) and 1 ft (east): King County, King County; WA.

   Online Links:

   • None

   Other_Citation_Details: None

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -122.44

   East_Bounding_Coordinate: -122.23

   North_Bounding_Coordinate: 47.74

   South_Bounding_Coordinate: 47.49

3. What does it look like?

   <http://www.metrokc.gov/gis/sdc/raster/ortho/images/Ortho2007KCExtent.jpg> (JPEG)

   Extent of project area showing separate resolution areas by township

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

   Beginning_Date: 27-Jun-2007

   Ending_Date: 30-Aug-2007

   Currentness_Reference: ground condition

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

   Geospatial_Data_Presentation_Form: Raster image 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, type Pixel

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

      Grid_Coordinate_System_Name: State Plane Coordinate System

      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 Feet

      The horizontal datum used is North American Datum of 1983; 1991 correction.
      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?

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

2. Who also contributed to the data set?

   Pictometry International Inc

3. To whom should users address questions about the data?

   Mike Leathers
   KCGIS-Center
   GIS Data Coordinator
   201 S Jackson St
   Seattle, WA 98104
   USA
   

   206-263-4867 (voice)
   

Color orthophoto imagery for King County and portions of adjoining counties. Portion of larger Pictometry package that contains their proprietary oblique and orthogonal view imagery for same project area.

1. From what previous works were the data drawn?

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

   Date: Feb-2008 (process 1 of 8)

   Data acquired from Pictometry on a stand-alone server connected to the King County LAN.

   Date: Feb-2008 (process 2 of 8)

   The imagery was in Pictometrys sector tiling scheme. This data was not reclipped to King Countys standard 7500 tiling scheme. Instead, MrSid v6 project files were created from all sector tiles (approximately 0.5 x 0.5 miles square) that fall whole ar part into the township tile. These tiles were mosaicked into a single sid file at 20x compression. Because of the rotation inherent in the sector pieces, introduced during reprojection by Pictometry, the edges of the mosaics are not orthogonal and thus tile edges show black (0,0,0) masks.

   Date: May-2008 (process 3 of 8)

   Image data was imported into separate SDE raster feature dataset mosaics (GISPROD.Raster). REG_07NAT_050 contains the portion of the project at 0.5 foot (6 inch) resolution and REG_07NAT_100 contains the portion of the project at 1.0 foot resolution. Import parameters include jp2000 compression at 75% quality. Mosaics were pyramided upon completion of import using jp2000 compression.

   Date: May-2008 (process 4 of 8)

   All 0.5 foot resolution image tiles were resampled to 1.0 foot pixel using NEAREST NEIGHBOR. These were combined with the existing 1.0 foot resolution data to complete a full set of 1.0 foot resolution data for possible submission to the USGS for use in the National Map program. The original 1.0 foot resolution data has a TFW world file as originally supplied by Pictometry. However the imagery resampled from the 0.5 foot imagery used ArcTools GP tools that produced a GEOTIFF which do not have world files.

   Date: May-2008 (process 5 of 8)

   All 1.0 foot resampled imagery was resampled to 2.0 foot pixel resolution for use in creation of higher-level mosaics. This resolution was adopted after tests of creating required mosaics at 1.0 foot and 1.5 foot resolutions were not successful. Resampling was performed using NEAREST NEIGHBOR. The original 1.0 foot resolution data has a TFW world file as originally supplied by Pictometry. However all the imagery was resampled using ArcToolBox GP tools which produce a world file without a TFW.

   Date: May-2008 (process 6 of 8)

   King County Zone Tile mosaics were created from 2.0 foot resampled imagery. MrSid V5 software was used to create the level 3 mosaics with a compression ratio of 20x.

   Date: May-2008 (process 7 of 8)

   Multiple attempts were made to create a full project area (KEYREGION) mosaic from the imagery. Even at 2.0 foot resolution a single mosaic was not successful. Rather a west county mosaic (REG_07N050.sid) and an east county mosaic (REG_07N100.sid) were created. Keeping with general practice the last three integer values of the name reflect the GSD (ground sample distance) of the initial image resolution, not the resolution of the final mosaic. KEYREGION components are intended to represent a lower-resolution, large extent, version of the data set. In this case the west county mosaic approximates the extent of the original 0.5 foot resolution data and the east county mosaic approximates the extent of the original 1.0 foot resolution data. MrSid V5 was used to create the mosaics (level 3) using 50X compression

   Date: May-2008 (process 8 of 8)

   All original Pictometry sector tile data (the data used to create the draft orthos and all subsequent mosaics) was copied to Plibrary3 idxp7500 ORTHO_2007KC07_NAT folder. Even though these tiles are not in the King County standard scheme, they were placed here to serve as full-resolution source data archive.

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

1. How well have the observations been checked?

   There are no attributes associated with these raster data formats.

2. How accurate are the geographic locations?

   Forty-nine (49) ground control points, provided by KC Road Services, were identified on the imagery. X-Y coordinate points were collected and X and Y offset (Ground control minus Photo target) and RMS analysis was performed. X-error ranged from (-4.71 feet) to (3.54 feet). Y-error ranged from (-1.27 feet) to (8.83 feet). A graphic depiction of the control locations and the error can be found in <http://www.metrokc.gov/gis/sdc/raster/ortho/images/Pictometry2007ControlToPhotoRMSAnalysis.jpg>. A spreadsheet of the tabular information can be found at <http://www.metrokc.gov/gis/sdc/raster/ortho/Pictometry2007ControlToPhotoRMSAnalysis.xls>. Overall RMS (root-mean square error) is calculated as 1.45 feet (X) and 1.93 (Y).

3. How accurate are the heights or depths?

   Not Applicable

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

   Tiles were created or all standard township-range tiles. The full extent of the project area imagery extends beyond the tile bounds in some areas. Zone and KeyRegion mosaics were created from all available data.

   West county (Neigborhood) imagery was acquired from 20080627 through 20070815. East county (Community) imagery was acquired from 20070725 through 20080830. Image-by-image acquisition information is listed in spatial indexes that contain acquistion information. These indexes can be found in the Plibrary3>Reference>Indexes>Pictometry07 as:

   staoblwaking07_cob_with_date (Standard Oblique WAKING07 Community Oblique with date) staoblwaking07_nob_with_date (Standard Oblique WAKING07 Neighborhood Oblique with date) staortwaking07_cor_with_date (Standard Ortho (vertical) WAKING07 Community Ortho (vertical) with date staortwaking07_nor_with_date (Standard Ortho (vertical) WAKING07 Neighborhood Ortho (vertical) with date

   The date of each image is also part of the image file itself. The set of integers just before the file-type suffix (such as 070814) refers to standard form 20070814 or August 14 2007.

   The Sector tiles are created from the underlying vertical (ortho) components. The dates associated with the images, either in their indexes, or in the file names themselves, refers to this post-acquisition construction date. Do not use these dates as an indicator of the image acquisition.

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

   Township-Range tiles are created from a mosaic of Pictometry's sector tiles. Some tiles will be a combination of 1.0 foot and 0.5 foot imagery.

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

Access_Constraints:

Access to the data is limited to King County government agencies. The data is not to be redistributed in digital form to any other users or entities.

Use_Constraints:

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 Department of Natural Resources and Parks/KCGIS-Center.

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

   Mike Leathers
   KC 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?

   txxryy_07n050.sid for 0.5 foot GSD resolution imagery. txxryy_07n100.sid for 1.0 foot GSD resolution imagery

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?

Dates:

Last modified: Feb-2008

Metadata author:

Mike Leathers
KCGIS-Center
GIS Data Coordinator
201 S Jackson St
Seattle, WA 98104
USA

206-263-4867 (voice)
firstname.lastname@metrokc.gov

Metadata standard:

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