GIS Data Catalog

Elevation Contour Lines for King County - 20 Foot Index Contours

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Summary

20 foot interval elevation contour lines for King County, derived primarily from 2021 lidar.

Description

Twenty (20) foot interval elevation contours for King County, derived primarily from 2021 lidar.

The 20 foot contours are a subset of the 5 foot contour layer.The contour interval represents a best compromise between the vertical and horizontal accuracy of the source data and the need for a general use cartographic and analysis product.

The data provide a reasonable depiction of the general shape of the land, useful for determining general landform, slope, and elevation.

These contours are provided only as an interpretation of the earth's surface for reference use and do not replace the need for a professional land survey.

Layer information

Layer Name	contour020_line
Subject Category	Topography
Title	Elevation Contour Lines for King County - 20 Foot Index Contours
Feature Count	127274
Feature Type	Line
Next Update	Irregular
Spatial reference	EPSG:2926
Control ID	85
Place Keywords	Washington State, Pacific NW, King County, Seattle
Theme Keywords	Contours, Elevation Data, Digital Elevation Model, Elevation
Supplemental Information	None

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Attribute information

OBJECTID From ESRI	Description Internal feature number. Domain 2659999
ELEVATION From KCGISC	Description Elevation of contour isoline in feet Domain Not Found
SHAPE From ESRI	Description Feature geometry. Domain Coordinates defining the features.
Shape.STLength() From SQL Server	Description Returns the total length of the elements in a geometry instance. Domain Double

Contact information

Maintained by	KCGIS Center
Primary	KCGIS Center giscenter@kingcounty.gov

Terms of Use

License	Terms of use and copyright

Use this Data

Links How to use in ArcGIS Pro
Sharing Status	Public

Summary

20 foot interval elevation contour lines for King County, derived primarily from 2021 lidar.

Description

Twenty (20) foot interval elevation contours for King County, derived primarily from 2021 lidar.

The 20 foot contours are a subset of the 5 foot contour layer.The contour interval represents a best compromise between the vertical and horizontal accuracy of the source data and the need for a general use cartographic and analysis product.

The data provide a reasonable depiction of the general shape of the land, useful for determining general landform, slope, and elevation.

These contours are provided only as an interpretation of the earth's surface for reference use and do not replace the need for a professional land survey.

Contact information

Maintained by	KCGIS Center
Primary	KCGIS Center giscenter@kingcounty.gov

Terms of use and copyright

License	Terms of use and copyright

Change history

12/1/2021	County-wide lidar update for 2021.
7/29/2019	Lidar update 2019 from Cedar, Green, Snoqualmie, & South Vashon pts.
9/15/2017	Townships updated: t19r07, t20r04, t20r05, t20r06, t20r07, t21r02, t21r03, t21r04, t21r05, t21r06, t21r07, t21r08, t21r09, t21r10, t21r11, t22r02, t22r03, t22r04, t22r05, t22r06, t22r07, t22r08, t22r09, t22r10, t22r11, t23r02, t23r03, t23r04, t23r05, t23r06, t23r07, t23r08, t23r09, t24r03, t24r04, t24r05, t24r06, t24r07, t24r08, t25r03, t25r04, t25r05, t25r06, t25r07, t25r08, t25r09, t25r10, t26r03, t26r04, t26r05, t26r06, t26r07, t26r08, t26r09, t26r10, t27r03, t27r04, t27r05, t27r06, t27r07
10/25/2016	Contours are derived from the latest DGM mosaic model. A 5 foot county wide contour layer is maintained in SDE Township DGM are extracted from the mosaic, contoured at 5 feet, the old township selected and deleted, and the new contour township appended back. Separate township layers are produced for posting to shapefiles and ftp portal. 5 Index contour layers for the county are also produced by selection from the master county wide 5 foot contour layer. 10, 20, 40, 50 and 100 foot contour indexes for the county are produced.
11/28/2008	Tiles are clipped from contour005 using the 7500 index squares. Contours are then converted into Autocad version 2004 DXF format.
11/26/2006	Produce tile list of DXF contours needed by intersecting p_lidar_all extent layer with index layer idxp7500. Write python script \images\ElevMaint\ctr27500\clip_dxf3.py to: Check for existence of DXF file If no file, then Select each tile. Build a clip. Clip SDE layer GISPROD plib.sde.plibrary.TOPO.contour005_line. ExportCAD_conversion using DXF_R2004 option.
Update 7	Townships updated: t21r04, t21r05, t23r07, t24r07,
Update 8	2016 Quantum Spatial lidar update for western part of county. Township contours updated: t19r08, t19r09, t19r10, t20r07, t20r08, t20r09, t20r10, t21r07, t21r08, t22r07, t22r08, t22r09, t22r10, t22r11, t23r07, t23r08, t23r09, t23r10, t23r11, t24r07, t24r08.
Update 9	Contours built from dgm township GRIDs, neat clipped, then appended together without edge matching.
Update 10	Data from 2004 3di West for Snoqualmie, Green River Study was integrated into master elevation database. This new elevation control was assembled from stereo pair orthoimagery, and approximates 2-foot contour accuracy necessary for FEMA flood plain mapping. The TIN surface created for the project was converted to a point dataset and then incorporated into the elevation database similar to the original lidar data. Data from 2007 Ground LiDAR ascii data from Watershed Science for parts of White River are integrated into master elevation database. This is the first update that was converted from Arc\Info GRID\AML to ARCGIS SDE RASTER\Python. See documentation: DGM Update Procedure.doc The following townships were updated: T19R06 T19R07 T21R04 T21R05 T21R06 T22R04 T22R05 T23R04 T23R05 T24R04 T24R07 T25R06 T25R07 T26R06 T26R07 T27R06.