Spatial Data Catalog

Internal feature number.

Sequential unique whole numbers that are automatically generated.

Feature geometry.

Coordinates defining the features.

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Length of feature in internal units.

Positive real numbers that are automatically generated.

Area of feature in internal units squared.

Positive real numbers that are automatically generated.

Ground LiDAR data from Quantum Spatial dated 2017 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Quantum_Spatial _2017.html for vendor metadata. The following townships were updated: T20R04 T21R04 T21R05 T23R07 T24R07

Ground LiDAR data from Quantum Spatial dated 2016 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Quantum_Spatial _2016.html for vendor metadata. The following townships were updated: T19R06 T19R07 T19R08 T19R09 T19R10 T20R04 T20R05 T20R06 T20R07 T20R08 T20R06 T20R07 T20R08 T20R09 T20R10 T21R02 T21R03 T21R04 T21R05 T21R06 T21R07 T21R08 T22R02 T22R03 T22R04 T22R05 T22R06 T22R07 T22R08 T22R09 T22R10 T22R11 T23R03 T23R04 T23R05 T23R06 T23R07 T23R08 T23R09 T23R10 T23R11 T24R03 T24R04 T24R05 T24R06 T24R07 T24R08 T24R09 T25R03 T25R04 T25R05 T25R06 T25R07 T25R11 T25R12 T25R13 T26R03 T26R04 T26R05 T26R06 T26R07 T26R08 T26R10 T26R11 T26R12 T26R13

Ground LiDAR data from Quantum Spatial dated 2015 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Quantum_Spatial_2015.html for vendor metadata. The following townships were updated: T21R02 T22R02 T21R03 T22R03 T20R04 T21R04 T21R05 T22R05 T19R06 T19R07 T20R06 T20R07 T22R06 T22R05 T23R06 T24R07 T25R07 T25R08 T22R09 T22R10 T23R08 T23R09 T24R08 T24R09

Ground LiDAR data from Watershed Science dated 2014 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Watershed_Science_2014.html for vendor metadata. The following townships were updated: T23R03 T27R03 T27R04 T28R04 T29R04 T21R05 T22R04 T23R04 T23R05 T22R06 T23R06 T22R07 T23R07 T21R08 T22R08 T23R08 T21R09 T22R09 T23R09 T21R10 T22R10 T24R07 T25R05 T25R06 T25R07 T25R08 T25R09 T26R05 T26R06 T26R07 T26R08 T26R09 T27R05 T27R06 T27R07 T28R05 T28R06 T28R07 T29R05

Ground LiDAR data from Watershed Science dated 2013 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Watershed_Science_2013.html for vendor metadata. The following townships were updated: T21R05 T22R05 T20R06 T22R05 T23R05 T22R06 T23R06 T22R07 T23R08 T24R07 T24R08 T25R06 T25R07 T264R06 T26R07 T26R10 T26R11 T26R12 T27R07 T27R08 T27R09 T27R10 T28R08 T28R09

Ground LiDAR data from Watershed Science dated 2012 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Watershed_Science_2012.html for vendor metadata. The following townships were updated: T23R02 T22R03 T20R04 T21R04 T20R05 T21R05 T21R06 T24R06 T25R06 T25R07 T24R07

Data from 2004 3di West for Snoqualmie, Green, & White 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. The following townships were updated: T19R06 T19R07 T21R04 T21R05 T21R06 T22R04 T22R05 T23R04 T23R05 T24R04 T24R07 T25R06 T25R07 T26R06 T26R07 T27R06

Added USGS 10m DEM data to tiles at the outer edge of the current data set. Two types of tiles were produced - tiles completely comprised of USGS elevation points and tiles that are a merge between the lidar elevation data and the USGS points. Only ASCII tiles were created. The USGS elevation data was not integrated into TINs, Hillshades or any higher-level products. 197 GS tiles were produced. The USGS DEM was clipped to the tile boundary, resampled to 12 foot, and exported as ID,X,Y,Elevation, where ID is a unique serial ID. For the JS tiles (170), both the existing lidar and new USGS point datasets were converted to coverages (USGS first to Lattice, then to point, Lidar first to TIN then to point). Using x_dgmasc.shp, which defines the extent of the lidar data, the USGS points that fell within the lidar extent were erased and the lidar points were clipped to the boundary to create a well-defined neat line. The two resulting coverages were unloaded to delimited files X,Y,Z and then appended. The appended file was then AWKed to create ID,X,Y,Z to create tileabb_dgmjs.asc The completed file was TINNed and hillshaded for quality control inspection. Finally, both the complete GS and JS tiles were zipped and placed in the SDW library.

Add Bathemetry data for Puget Sound, Lake Washington, Lake Sammamish. Indentify which idxp7500 tiles that have bathymetry data to be processed and build tinlist. Digitize and replace waterbody outlines of coverage lakebathy using KC2002 2ft JP2 format imagery at scale 1:2500. Determine each lake in lakebathy surface elevation using lidar and adjust lakebathy contour line elevation values to the lidar. Append all waterbody Edge Of Water arcs into one coverage for erasing water surface data and EOW hardline for TIN production. run j:phase2\bathy\mktin_puget.aml , mktin_wash.aml, mktin_sam.aml Creates new tins using lidar tile tin to points from plibrary3, bathymetry points: reg_ps_bthy (Puget Sound), reg_wl_bthy (Lake Washington), reg_ls_bthy (Lake Sammamish) arcs for hard breakline around the lake. Build dgm grid, hillshade grid and image.

Some upland project area tiles processed on the Windows OS with an unix awk emulation command failed to properly enumerate a unique id for each record for the ascii files containing the raw elevation data in the 7500 tiles. In other instances ascii files still contained a constant value of '1' in the ascii record, a holdover from the Arc Info Tin generation process that was not properly enumerated to a unique sequential id. Finally a review of the Ascii files indicated that some tiles still contained a final record containing the value 'end', again a requirement of the TIN generation process that was not removed. All dgm ascii files tiled in the 7500 blocks were reprocessed using an updated awk command that was tested to successfully generate a unique serial integer for all records up to the largest ascii file size. A windows version of grep was used with the -v flag to remove all occurrences of 'end' or 'End' from any files where this occurred. The original warehouse files were unzipped, processed as indicated above and replaced. A final inspection routine unpacked a copy of the files. A windows version of the unix tail command was used to create a text file of the last 10 records of each file. These were inspected to ensure sequential numbering was present to the end of the file and that the file terminated successfully.

Review of version 1 township-range tiles indicated substantial edge effects at the boundary where one 7500 tin overlapped an adjacent 7500 tin. Though systemic this did not occur along all boundaries. The 100 foot overlap built into the tin extent was designed to reduce edge effects when lattices derived from the tins were merged. However there continued to be an effect at the edge of the 100 ft lattices possibly due to how the lattice was calculated at the edge. Adjustments were made to the processing routines to clip the lattice generated from the tin to 12 feet outside the tile bounds. This still provided an overlap buffer with adjacent tiles yet substantially improved the quality of the merge.

King County DGM Process Step 7: The composite lattice is input to the ArcInfo HILLSHADE command with AZIMUTH = 315, ALTITUDE = 45 and ALL arguments. The output grid is converted to a TIFF image with world file with the GRIDIMAGE command with NONE for colormap and NO on compression to create a default grey-scale hillshade for general use. The composite ArcInfo lattice and Hillshade TIF are inspected for completeness and general overall quality and copied to Data Warehouse.

King County DGM Process Step 3: Mutiple idxp7500 DGM TINs comprise a single idxptrmbr (township-range) tile. Each of these TINs was converted to a ArcInfo lattice using the TINLATTICE command with a six (6) foot posting for the township level tiles. Each of these lattices has an actual extent of 7700 feet in both x and y (where there is data for the full extent) due to the 100 foot buffer established during TIN creation. Depending on the orientation of the township-range tile bound to the underlying idxp7500 grid, between 15 and 25 individual lattices are created which are then MERGED in GRID to create a composite lattice.

King County DGM Process Step 4: Any negative values in the resulting composite lattice are set to NULL. This is done to eliminate potential erroneous values and potentially confusing statistics. This tends to eliminate negative values associated with water features, as well as other spurious values. A 3x3 focalmean filter is executed against all NULL values to infill any inliers that have now been converted to NULL with an elevation approximation based on adjacent values. The 100 foot overlap of the input lattices reduces the possiblity of creating strong null value edges between tiles so this 3x3 filter is considered as filling only localized NULL 'holes' in the data. The original unaltered values of any given data point can be found in the underlying TIN or ASCII point file if access to the unmassaged data is necessary.

King County DGM Process Step 1: After receipt from 3di Technologies, the data media was cataloged, and the media contents were logged. The ASCII files were retiled into the King County idxp7500 tiling scheme. This resulted in creation of larger files where several 1 x 1 km 3di tiles were appended and clipped to form one 7500 ft x 7500 King County tile. The ASCII records were also appended with a integer identifier resulting in a final record format of identifier, easting, northing, and elevation value.

King County DGM Process Step 6: The composite lattice created by merging the individual 7700 tiles extends beyond the extent of the township-range tile. The composite lattice is clipped to the bounds of the township-range tile using the GRID GRIDCLIP function. The resulting clipped lattice is defined with projection information using the PROJECTDEFINE command.

King County DGM Process Step 2: Digital Ground Model (bare-earth) .gen files were built for input to the TIN creation function. The .gen files included all points of the subject tile plus a 100-foot buffer of all adjacent tiles. The composite ASCII .gen file was AWKed to create an output file of form: 1,easting, northing, elevation. The constant value of 1 is used to indicate that all points should be treated as Masspoints during the tinning process. The retiled ASCII point files were built into TINs using ArcInfo CREATETIN command with no (0.0) proximity tolerance.

King County DGM Process Step 5: A NULL editmask delineating the open water of the Puget Sound and all areas beyond the project area buffer elsewhere was applied to mask out all remaining 'out-of-bounds' elevation values. This is done mainly to help 'clean-up' the water areas but also cleaned up along the edge of the project area. The boundary used along the shoreline was designed to be conservative to avoid clipping any valid nearshore elevation values. The underlying TINs and ASCII point files can be used to recover, if necessary, any points removed by this edit.

Vendor DGM Production Step 1: LiDAR data processing was used to produce the x,y,z elevation points using vendor proprietary lidar data processing software. Within this integrated process an atmospheric correction was made, which is especially important in regions of relatively low elevation.

Vendor DGM Production Step 2: Data by flight line was combined in a merge process that eliminates redundant points. Data was also clipped into more manageable one km x one km bounds. Noise or anomalous returns were filtered from all data during this processing step. The data was quality checked using commercial software, Spectra Precision TerraModel and TerraVista. In order to produce a ground surface DEM, vegetation removal was performed on the last return elevation points data by identifying the laser returns from above ground vegetation. This proprietary algorithm is capable of removing between 90-95% of the trees and most other prominent above ground vegetation from the data. The data was triangulated into contours and any remaining vegetation or manmade structures and buildings were identified visually and interactively removed from the data. The data was triangulated again, contoured and visualized to see the effect of the additional elevation point removal and for any final edits that might be necessary.

Vendor DGM Production Step 4: Bare earth return point data was transferred to media for delivery to Client in a comma/space delimited ASCII file of format easting,northing,intensity-value.

Vendor DGM Production Step 3: All elevation data was processed on a point by point basis for ellipsoid to orthometric height conversion using the National Geodetic Survey (NGS) Geoid Model, GEOID99. Datum and coordinate system conversion from WGS84 to the Washington State Plane coordinate system was performed using U.S. Army Corps of Engineers CorpsCon software algorithms.

Ground LiDAR data from Watershed Science dated 2010 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Watershed_Science_2010.html for vendor metadata. The following townships were updated: T19R06 T20R06 T20R07 T21R05 T22R04 T22R06 T22R07 T23R05 T23R06 T23R08 T23R09 T24R05 T24R07 T24R08 T25R07 NOAA bathyemetry extented for Duwamish for T24R04

Ground LiDAR ascii data from Watershed Science dated 2007 for parts of Snoqualmie, Green, & 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: T20R05 T21R04 T21R05 T21R06 T23R08 T24R07 T25R07 T26R07

Ground LiDAR data from Watershed Science dated 2011 was integrated into master elevation database. See https://www5.kingcounty.gov/sdc/raster/elevation/LiDAR_Digital_Ground_Model_Elevation_Watershed_Science_2011.html for vendor metadata. The following townships were updated: T19R06 T20R04 T20R05 T20R06 T21R04 T21R05 T22R04 T22R06 T22R07 T23R04 T23R05 T23R06 T23R07 T23R08 T23R09 T23R09 T24R07 T24R08 T24R09 T25R06 T25R07 T26R05 T26R06