King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle, WA 98104

+ 47.59909 N
- 122.33136 W

+ 47°  35' 56.72"
- 122° 19' 52.90"


7500-FT Tiling Status for KC Raster Datasets

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Layer name: RASTSTAT_7500
Subject category: survey
Title: 7500-FT Tiling Status for KC Raster Datasets
Feature Count: 0
Feature Type: Polygon
Abstract: A spatial tiling index designed for storage of file-based image and other raster (i.e., LiDAR elevation, landcover) data sets. A regular grid with origin at 0,0 of the Washington North State Plane Coordinate System, with grid cells defined by orthogonal bounds 7500 feet long in easting and in northing. Only those cells currently involved in one of several image/raster data projects for King County and southwestern Snohomish County are labelled, though the labeling scheme can be extended. The name of the spatial index is derived from the acronym (I)n(D)e(X) (P)olygons at the (7500) foot tile level, or idxp7500. Cell label is a row-id cocantenated with a column-id generating a four-character identifier that uniquely identifies every cell. The row portion of the identifier is a two-character alpha code of the format aa, ab, ac.... ba, bb, etc. and the column portion is a two-digit integer value such as 01, 02, 03.... 11,12,13, etc. A composite cell identifier would be then, for example, aa01, aa02, .....ba11,ba12, etc. Not all image and raster data is stored at the tiling level represented by this index. Data is stored at this level if full-resolution, uncompressed data would generate larger than manageable file sizes at a larger tile size.
Purpose: This index is primarily a data processing, data storage level index which allows all raster and image data stored at this level to be maintained in a common, consistent tile and naming scheme. The index also serves as a useful central reference scheme for identification of real-world locations. This index level is useful for users of LiDAR-derived elevation data stored as TINS because TIN format data, as well as ASCII format data, are stored only at this tiling level. Imagery in native uncompressed format will also be stored only at this level. As each cell is defined with orthogonal edges relative the Washington State Plane coordinate system, it accomodates most common pixel resolutions of multiple ground sample distance (gsd) without partial pixel effects and without zero or NULL data 'splinters'.
Status: Complete
Updated: As needed
Time period of content: (single date,as YYYYMMDD):: 20030701
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Yes
Place Keywords: Seattle, Washington state, Pacific NW, King County, WA, Snohomish County, southwestern portion,
Theme Keywords: reference grids, survey, Image data, Raster data, Spatial index, Tiling index,
Lineage: Available
Supplemental Information: This spatial index is one of three index or tiling levels used to store King County image and raster data. Each higher index level is designed to build upon the lower levels, with the same data often stored at more than one level (though at different resolutions) to meet a range of business and software requirements. Individual shapefiles for each of the cells in this index are available in gisimage/images/reference/indexes/idxp7500_shp as 'tileabb'_bnd.shp.


Maintained by:
King County GIS Center
Primary: Victor High, Senior GIS Specialist, 206-263-4845
(How to e-mail a County contact)
Secondary: KCGIS Center; This mailbox is monitored during business hours.

Attribute Information

_TILE_ABBLC_Primary 'colloquial' identifier for each cell identical in value to the tile_abb, but where the alpha portion of the code is lowercase. Unique alphanumeric identifier comprised of two-character alpha code defining in which spatial column the cell exists cocantenated with a two-digit numeric code defining in which spatial row the cell exists.Unique alphanumeric code


Access: None

Use: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County.