2021 USGS Lidar: Thurston County, WA

Product: Classified LAS 1.4 files, formatted to 628 individual 4500ft x 4500ft covering the Thurston County project area.

Geographic Extent: This dataset and derived products encompass an area covering approximately 199,484 acres of Western Washington.

Dataset Description: The Thurston County Lidar project called for the planning, acquisition, and processing of lidar data collected to Quality Level 1 (QL1) standards. Project specifications are based on the U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2020 Revision A. The data was developed based on the NAD83 2011 horizontal datum and the NAVD88 Geoid 18 vertical datum. Data was projected in Washington State Plane South, U.S. feet. Lidar data was delivered as calibrated and classified LAS 1.4 files. Non-Vegetated Vertical Accuracy (NVA) was assessed using 30 check points located on bare earth in clear, unobstructed areas. Vegetated Vertical Accuracy (VVA) was assessed using 25 check points in Tall Grass, Forest, and Shrub landcover types. Single swath nominal pulse spacing (NPS) was designed to be 0.50 m at nadir. Aggregate Nominal Pulse Spacing (ANPS) was calculated to be 0.27 m using all valid first return points. Derived products include: Intensity Imagery, Hydro-flattened Bare Earth Digital Elevation Models (DEMs), maximum height surface rasters (DSM), swath separation images, and 3D waters edge breaklines.

Ground Conditions: Ground condition was free of snow and acquisition occurred free of smoke, fog and cloud cover.

This metadata supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

The purpose of the lidar data was to produce a high accuracy 3D dataset that meets all necessary standards laid out by the 3D Elevation Program and the Thurston County contract. The lidar point cloud data were used to create classified lidar LAS files, intensity images, hydro-flattened DEMs, maximum height surface rasters (DSM), swath separation images, and 3D breaklines of rivers and lakes within the study area.

USGS Contract No. G16PC00016

CONTRACTOR: NV5 Geospatial

Ground Control Points were acquired and calibrated by NV5 Geospatial

All lidar data acquisition, calibration, and follow-on processing were completed by NV5 Geospatial.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1",

"ldrsens" : "Riegl VQ-1560II",

"ldrmaxnr" : "15",

"ldrnps" : "0.50 m",

"ldrdens" : "4 ppsm",

"ldranps" : "0.27 m",

"ldradens" : "13 ppsm",

"ldrfltht" : "2,083",

"ldrfltsp" : "145",

"ldrscana" : "58.5",

"ldrscanr" : "Uniform Point Spacing",

"ldrpulsr" : "635",

"ldrpulsd" : "3.0",

"ldrpulsw" : "0.375",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.18",

"ldrswatw" : "2,233",

"ldrswato" : "55",

"ldrgeoid" : "Geoid 18"

},

"ldraccur" : {

"ldrchacc" : "0.00",

"rawnva" : "0",

"rawnvan" : "0"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points are identified in these files using the standard LAS Withheld bit.",

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit.",

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed, but Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare earth ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Low Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

},

"lasclass" : {

"clascode" : "20",

"clasitem" : "Ignored Ground Near Breaklines"

}

}}

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

Data is available online for bulk and custom downloads.

None

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

RiProcess, Applanix PosPAC, Microstation CONNECT, TerraScan Version 19, TerraModeler Version 19, TerraMatch Version 19, ESRI ArcGIS 10.3, Windows 10 Operating System

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

USGS Determined Vertical Accuracy

Non-Vegetated Vertical Accuracy (NVA) = 2 cm RMSE

Vegetated Vertical Accuracy (VVA) = 17.63 cm at the 95th Percentile

These LAS data files include all data points collected. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. No void areas or missing data exist. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Classified LAS files were tested by NV5 for vertical accuracy. All data is seamless from one tile to the next, no gaps or no data areas.

Data is backed up to tape and to cloud storage.

The Thurston County lidar was ingested into the Data Access Viewer for custom product generation by leveraging USGS hosted Entwine Point Tiles.