IDXPTRMBR - Township Tiling Index for King County Raster Data

Description

Layer name: IDXPTRMBR
Subject category: survey
Title: IDXPTRMBR - Township Tiling Index for King County Raster Data
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. An irregular grid of overlapping polygons, each enclosing its respective Public Land Survey System (PLSS) township in an orthogonal polygon minimally encompassing all portions of that township, i.e., minimum bounding rectangle. The amount of overlap between adjacent tiles varies depending on the geometry of the underlying township. Currently extended to include all townships within or partially within King County as well as those townships in the southwestern portion of Snohomish County included within King County's ESA/SAO project area. The name of the spatial index is derived from the acronym (I)n(D)e(X) (P)olygons for (T)ownship-(R)ange, (M)inimum (B)ounding (R)ectangle, or idxptrmbr. Tile label is the t(township number)r(range number)as in t24r02. The meridian zone identifiers, N for townships and E for range is inferred as this index is intended as a local index for ease of use by the majority of users of GIS data. Lowercase identifiers are used for consistency between Unix and Windows OS storage. This index or tile level is the primary user-access level for most LiDAR elevation, orthoimagery and high-resolution raster landcover data. However, not all image and raster data is stored at the tiling level if a given data's resolution does not justify storing the data as multiple tiles.
Purpose: This index is the primary User Access level for image/raster datasets. It provides multiple file-based data sets to be accessed at full or near full resolution in a common, consistent tile and naming scheme. The index also serves as a useful central reference scheme for identification of real-world locations as it references the commonly used township-range grid of the PLSS. As each cell is defined with orthogonal edges relative the Washington State Plane coordinate system, and is defined by easting and northing bounds rounded to the nearest 100 foot, it accomodates most common pixel resolutions of multiple Ground Sample Distance 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: Snohomish County; southwestern portion, Seattle, Washington state, Pacific NW, King County, WA,
Theme Keywords: reference grids, survey, Image data, Raster data, PLSS, Spatial Index, Township and Range, Public Land Survey System, 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. The index level lower than this is the idxp7500 index. The index level immediately higher than this is idxpzone. 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/idxptrmbr_shp as 'tileabb'mbr.shp.

Contacts

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; giscenter@kingcounty.gov. This mailbox is monitored during business hours.

Attribute Information

Constraints

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.