67484
2017 WA DNR Lidar DEM: Tacoma Water Service Area - Green River, WA
Data Set
Published / External
49404
DEMs - partner (no harvest)
Project
Completed
2017
No metadata record was provided with the data. This record is populated with information from the Quantum Spatial, Inc. technical report downloaded from the Washington Dept. of Natural Resources Washington Lidar Portal. The technical report is available for download from the link provided in the URL section of this metadata record.
In September 2017, Quantum Spatial (QSI) was contracted by the Washington Department of Natural Resources (WADNR) to collect Light Detection and Ranging (LiDAR) data and digital imagery in the winter of 2017 and summer of 2018, respectively, for the Tacoma Water Service Area (TWSA) site in Washington. This contract also incorporates LiDAR data and digital imagery collection and processing over additional nearby sites, including the Green River Watershed, Green River Corridor, and a selected portion of the Green River Watershed which will be used for forestry analytics. QSI provided TWSA Delivery 1 on April 6th, 2018, representing approximately 94% (104,495 acres) of the site. TWSA Delivery 2 represents the remaining 6% (7,186 acres) of the site. This data report summarizes the collection and processing of the full extent of the TWSA site (111,681 acres), consisting of Delivery 1 and Delivery 2 areas of interest. Data were collected to aid WADNR in assessing the topographic and geophysical properties of the study area.
In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from are also available. These data are available for download at the link provided in the URL section of this metadata record.
Data were collected to aid WADNR in assessing the topographic and geophysical properties of the study area.
Theme
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Theme
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION > DIGITAL ELEVATION/TERRAIN MODEL (DEM)
Theme
ISO 19115 Topic Category
elevation
Spatial
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Spatial
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > WASHINGTON
Spatial
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
Instrument
Global Change Master Directory (GCMD) Instrument Keywords
LIDAR > Light Detection and Ranging
Platform
Global Change Master Directory (GCMD) Platform Keywords
Airplane > Airplane
Office for Coastal Management
Charleston
SC
Data Set
Elevation
None Planned
Model (digital)
Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.
Quantum Spatial, Inc., Washington Dept. of Natural Resources
Data Steward
2022
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Distributor
2022
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Metadata Contact
2022
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Point of Contact
2022
Organization
NOAA Office for Coastal Management
NOAA/OCM
coastal.info@noaa.gov
2234 South Hobson Ave
Charleston
SC
29405-2413
(843) 740-1202
https://coast.noaa.gov
NOAA Office for Coastal Management Home Page
Online Resource
Ground Condition
-122.591663
-121.737143
47.340071
47.065263
Range
2017-12-05
2017-12-06
Collection dates for Delivery 1
Range
2017-12-09
2017-12-10
Dates of collection for Delivery 1
Discrete
2017-12-10
Collection date for Delivery 2
Range
2018-11-11
2018-11-12
Collection dates for Delivery 2
Yes
Projected
EPSG:2927
NAD83(HARN) / Washington South (ftUS)
NAD83 (High Accuracy Reference Network)
GRS 1980
6378137
298.257222101
NAD83(HARN)
SPCS83 Washington South zone (US Survey feet)
Lambert Conic Conformal (2SP)
1
Easting
X
US survey foot
east
2
Northing
Y
US survey foot
north
Vertical
EPSG:6360
NAVD88 height (ftUS)
North American Vertical Datum 1988
1
Gravity-related height
H
US survey foot
up
Unclassified
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.
2021-07-15
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9550/details/9550
2022
Organization
NOAA Office for Coastal Management
Customized Download
Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base. Change to an orthometric vertical datum is one of the many options.
Zip
Zip
2021-07-15
https://noaa-nos-coastal-lidar-pds.s3.us-east-1.amazonaws.com/dem/WA_Green_Rvr_TWSA_DEM_2017_9550/index.html
2022
Organization
NOAA Office for Coastal Management
Bulk Download
Bulk download of data files in GeoTiff format, WA State Plane South NAD83(HARN) US survey feet coordinates and orthometric heights in feet.
GeoTIFF
GeoTIFF
https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/9549/supplemental/wa2017_twsa_m9549.kmz
Browse graphic
Browse Graphic
KML
This graphic displays the footprint for this lidar data set.
https://coast.noaa.gov/dataviewer/
NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
Online Resource
HTML
The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.
https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=9549/details/9549
Custom Point Download
Online Resource
Zip
Link to custom download, from the Data Access Viewer (DAV), the lidar point data from which these raster Digital Elevation Model (DEM) data were created.
https://lidarportal.dnr.wa.gov/download?ids=1341
Lidar Report
Online Resource
pdf
Link to the Quantum Spatial, Inc. Technical Lidar Report from the Washington Lidar Portal.
Absolute accuracy was assessed using Non-Vegetated Vertical Accuracy (NVA) reporting designed to meet guidelines presented in the FGDC National Standard for Spatial Data Accuracy3. NVA compares known ground check point data that were withheld from the calibration and post-processing of the LiDAR point cloud to the triangulated surface generated by the unclassified LiDAR point cloud as well as the derived gridded bare earth DEM. NVA is a measure of the accuracy of LiDAR point data in open areas where the LiDAR system has a high probability of measuring the ground surface and is evaluated at the 95% confidence interval (1.96 * RMSE).
The mean and standard deviation (sigma) of divergence of the ground surface model from quality assurance point coordinates are also considered during accuracy assessment. These statistics assume the error for x, y and z is normally distributed, and therefore the skew and kurtosis of distributions are also considered when evaluating error statistics. For the Tacoma Water Service Area survey, 25 ground check points were withheld from the calibration and post processing of the LiDAR point cloud, with resulting non-vegetated vertical accuracy of 0.264 feet (0.081 meters) with 95% confidence or 4.1 cm RMSE as compared to unclassified LAS, and 0.293 feet (0.089 meters) with 95% confidence as compared to the bare earth DEM, or 4.5 cm RMSE .
QSI has high standards and adheres to best practices in all efforts. In the laboratory, quality checks are built in throughout processing steps, and automated methodology allows for rapid data processing. QSI's innovation and adaptive culture rises to technical challenges and the needs of clients like Washington DNR. Reporting and communication to our clients are prioritized through regular updates and meetings.
Yes
Unknown
Yes
NCEI-CO
Data is backed up to tape and to cloud storage.
The NOAA Office for Coastal Management (OCM) downloaded the GeoTiff files from the Washington Lidar Portal.
Washington Dept of Natural Resources
Organization
Washington Dept of Natural Resources
Originator
https://lidarportal.dnr.wa.gov/
Washington Lidar Portal
1
Planning:
In preparation for data collection, QSI reviewed the project area and developed a specialized flight plan to ensure complete coverage of the Tacoma Water Service Area LiDAR study area at the target point density of greater than or equal to 8.0 points/m2 (0.74 points/ft2). Acquisition parameters including orientation relative to terrain, flight altitude, pulse rate, scan angle, and ground speed were adapted to optimize flight paths and flight times while meeting all contract specifications.
Factors such as satellite constellation availability and weather windows must be considered during the planning stage. Any weather hazards or conditions affecting the flights were continuously monitored due to their potential impact on the daily success of airborne and ground operations. In addition, logistical considerations including private property access and potential air space restrictions were reviewed.
2
Ground Survey Points
Ground control surveys, including base stations, aerial targets, and ground survey points (GSPs) were conducted to support the airborne acquisition. Ground control data were used to geospatially correct the aircraft positional coordinate data and to perform quality assurance checks on final LiDAR data and orthoimagery products.
Ground survey points were collected using real time kinematic (RTK) and fast-static (FS) survey techniques. For RTK surveys, a roving receiver receives corrections from a nearby base station or Real-Time Network (RTN) via radio or cellular network, enabling rapid collection of points with relative errors less than 1.5 cm horizontal and 2.0 cm vertical. FS surveys compute these corrections during post-processing to achieve comparable accuracy. RTK surveys record data while stationary for at least five seconds, calculating the position using at least three one-second epochs. FS surveys record observations for up to fifteen minutes on each GSP in order to support longer baselines. All GSP measurements were made during periods with a Position Dilution of Precision (PDOP) of less than or equal to 3.0 with at least six satellites in view of the stationary and roving receivers.
GSPs were collected in areas where good satellite visibility was achieved on paved roads and other hard surfaces such as gravel or packed dirt roads. GSP measurements were not taken on highly reflective surfaces such as center line stripes or lane markings on roads due to the increased noise seen in the laser returns over these surfaces. GSPs were collected within as many flightlines as possible; however, the distribution of GSPs depended on ground access constraints and monument locations and may not be equitably distributed throughout the study area.
Base Stations
A combination of Washington State Reference Network (WSRN) Real-Time Network (RTN) base stations and a QSI-established monument were utilized for the Tacoma Water Service Area LiDAR project. Base stations were used to correct the flightline positional coordinate data, while QSIâÂÂs monument was used to support collection of ground survey points using real time kinematic (RTK) and fast static (FS) survey techniques.
QSI utilized seven existing base stations and established one new monument for the Tacoma Water Service Area LiDAR project. New monumentation was set a 6-inch PK nail with a reference washer. QSIâÂÂs professional land surveyor, Evon Silvia (WAPLS#53957) oversaw and certified the ground survey.
QSI utilized static Global Navigation Satellite System (GNSS) data collected at 1 Hz recording frequency for each base station. During post-processing, the static GNSS data were triangulated with nearby Continuously Operating Reference Stations (CORS) using the Online Positioning User Service (OPUS1) for precise positioning. Multiple independent sessions over the same monument were processed to confirm antenna height measurements and to refine position accuracy.
Monuments were established according to the national standard for geodetic control networks, as specified in the Federal Geographic Data Committee (FGDC) Geospatial Positioning Accuracy Standards for geodetic networks. This standard provides guidelines for classification of monument quality at the 95% confidence interval as a basis for comparing the quality of one control network to another. For the Tacoma Water Service Area LiDAR project, the monument coordinates contributed no more than 2.8 cm of positional error to the geolocation of the final ground survey points and LiDAR, with 95% confidence.
3
Airborne Survey
The Delivery 1 LiDAR survey was accomplished using a Leica ALS80 system mounted in a Cessna Caravan while the Delivery 2 LiDAR survey utilized a Riegl VQ-1560i system mounted in a Cessna Caravan. The Leica ALS80 and Riegl VQ-1560i laser systems can record unlimited range measurements (returns) per pulse. It is not uncommon for some types of surfaces (e.g., dense vegetation or water) to return fewer pulses to the LiDAR sensor than the laser originally emitted. The discrepancy between first return and overall delivered density will vary depending on terrain, land cover, and the prevalence of water bodies. All discernible laser returns were processed for the output dataset.
All areas were surveyed with an opposing flight line side-lap of greater than or equal to 50% (greater than or equal to 100% overlap) in order to reduce laser shadowing and increase surface laser painting. To accurately solve for laser point position (geographic coordinates x, y and z), the positional coordinates of the airborne sensor and the attitude of the aircraft were recorded continuously throughout the LiDAR data collection mission. Position of the aircraft was measured twice per second (2 Hz) by an onboard differential GPS unit, and aircraft attitude was measured 200 times per second (200 Hz) as pitch, roll and yaw (heading) from an onboard inertial measurement unit (IMU). To allow for post-processing correction and calibration, aircraft and sensor position and attitude data are indexed by GPS time.
4
Upon completion of data acquisition, QSI processing staff initiated a suite of automated and manual techniques to process the data into the requested deliverables. Processing tasks included GPS control computations, smoothed best estimate trajectory (SBET) calculations, kinematic corrections, calculation of laser point position, sensor and data calibration for optimal relative and absolute accuracy, and LiDAR point classification. Processing methodologies were tailored for the landscape. Brief descriptions of these tasks are shown below.
Lidar Processing Steps
Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and precise point positioning (PPP) techniques. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey. Software used - Waypoint Inertial Explorer v.8.7
Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las (ASPRS v. 1.2) format. Convert data to orthometric elevations by applying a geoid correction. Software used - Waypoint Inertial Explorer v.8.7 Leica CloudPro v. 1.2.4
Import raw laser points into manageable blocks (less than 500 MB) to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines. Software used - TerraScan v.18
Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration. Software used - TerraMatch v.18
Classify resulting data to ground and other client designated ASPRS classifications (Table 6). Assess statistical absolute accuracy via direct comparisons of ground classified points to ground control survey data. Software used - TerraScan v.18, TerraModeler v.18
Generate bare earth models as triangulated surfaces. Generate highest hit models as a surface expression of all classified points. Export all surface models as ESRI GRIDs at a 3.0 foot pixel resolution. Software user - TerraScan v.18, TerraModeler v.18, ArcMap v. 10.3.1
5
The NOAA Office for Coastal Management (OCM) downloaded this data set from the Washington Lidar Portal. The total number of files downloaded and processed was 17.
The data were in Washington State Plane South NAD83(HARN), US survey feet coordinates and NAVD88 (Geoid12B) elevations in feet. The bare earth raster files were at a 3 feet grid spacing. No metadata record was provided with the data. This record is populated with information from the Quantum Geospatial, Inc. technical report downloaded from the Washington Dept. of Natural Resources Washington Lidar Portal.
OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:
1. Used internal an script to assign the EPSG codes (Horizontal EPSG: 2927 and Vertical EPSG: 6360) to the GeoTiff formatted files.
2. Copied the files to https.
2022-06-28T00:00:00
Organization
Office for Coastal Management
OCM
2234 South Hobson Avenue
Charleston
SC
29405-2413
https://www.coast.noaa.gov/
67479
Data Set
2017 WA DNR Lidar: Tacoma Water Service Area - Green River, WA
Cross Reference
gov.noaa.nmfs.inport:67484
Rebecca Mataosky
2022-06-28T20:28:56
Kirk Waters
2024-01-10T19:25:43
2024-01-10
OCM Partners
OCMP
1002
Public
No
2022-06-28
1 Year
2023-06-28