Pictometry (under contract with King County), 200911, 2009 King County (Pictometry) Orthoimagery - 6 in (west) and 1 ft (east): King County, King County; WA.
This is a Raster data set. It contains the following raster data types:
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.
Pictometry International Inc
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 the same project area.
There are no attributes associated with these raster data formats.
One-hundred twenty-seven (127) ground control points, provided by KC Road Services and the City of Seattle, were identified on the imagery. X-Y coordinate points were collected and X and Y offset (Photo - Ground Control) and RMS analysis was performed. A spreadsheet of the tabular information can be found at <http://www5.kingcounty.gov/sdc/raster/ortho/photo_control_master_09n050_RMSError.xls>. Overall RMS (root-mean square error) is calculated as 3.27 feet (X) and 1.44 (Y).
Tiles were created for all standard township-range tiles. The full extent of the project area imagery extends beyond the tile bounds in some areas. The SDE mosaic, Zone and KeyRegion mosaics were created from all available data.
West county (Neigborhood) imagery was generally acquired during April and May, while the east county (Community) imagery was acquired from August through October to ensure snow-free conditions.
Image acquisition dates are available, but not via the township-range tiles because they are mosaicked from multiple images. Rather users must reference the image acquisition information for the individual vertical or oblique images or from the spatial indexes for these images.
The date of each image is part of the image (oblique or vertical) file itself. The set of integers just before the file-type suffix (such as 090814) refers to standard form 20090814 or August 14 2009. Be aware the the Sector tiles (part of the Pictometry image library) 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.
Alternatively, to correctly determine the acquistion date and time for an area you need to use the spatial indexes found in plibrary3/reference/indexes/Pictometry09.
ortho_image.shp for the every image resolved to YYYY/MM/DD HH:MM:SS ortho_dategrp.shp for images grouped (dissolved by YYYYMMDD)
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.
Imagery was captured over a span of five months in a block-type pattern, with infill areas. This less-than-optimal flight pattern resulted in noticeable temporal/vegetative variations in the mosaic tiles.
The Contractor was provided with high-quality digital ground model data (in ascii format) for use as a Digital Terrain Model for orthorectification. They were also provided with a street centerline model and an overpass/bridge layer to aid in seamline creation or elevated structure correction. Though the DTM data was used for the orthorectification, the vendor did not ameliorate any of the other non-rectified artifacts.
Somr tonal variation is also evident across many of the tiles due to variations in lighting conditions.
The mosaic tiles also show numerous examples of mis-alignment along seamlines with offsets and other artifacts that indicate the images of different vintage were mosaicked.
Are there legal restrictions on access or use of the data?
- Data is licensed by Pictometry to King County. It is not to be distributed except under one of the following conditions: (a) Cities and other non-state, non-federal, public service entities (fire districts, utility districts, etc.) can become licensed cost-share participants. The receiving agency or city is required to submit, and is bound by, a licensing agreement. Interested parties should contact the GIS Data Coordinator at the KCGIS Center for additional details. (b) Consultants performing a specified Scope of Work (SOW) for a licensed entity, either under a contract or a formal Memorandum of Understanding (MOU), can be provided with a limited amount of data. The data provided cannot exceed the extent or the scope required for the SOW. Data can only be used for the current, defined SOW for which it is provided. The consultant or MOU participant may not redistribute or sell the data in any form. The data must be deleted from the recipients servers or harddrives upon completion of the contract or MOU.
- 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.
txxryy_09n050.sid for 0.5 foot GSD resolution imagery. txxryy_09n100.sid for 1.0 foot GSD resolution imagery
King County disclaims any warranty of use of any digital product or data beyond that for which it was designed.