2014 PSLC Lidar: Willapa River Valley (Delivery 1), WA

In January, 2014 WSI, a Quantum Spatial (QSI) company, was contracted by the Puget Sound LiDAR Consortium (PSLC) to collect Light Detection and Ranging (LiDAR) data for the Willapa River Valley site in Washington. This initial delivery is for the 35,472 acre western area within the greater study area. Due to weather and resource constraints, the entire Area of Interest (AOI) has not yet been acquired. The remaining acquisition is scheduled to occur during the Fall 2014 leaf-off season. Data are being collected to aid PSLC in assessing the topographic and geophysical properties of the study area. This report accompanies the delivery 1 LiDAR data, and documents contract specifications, data acquisition procedures, processing methods, and analysis of the final dataset including LiDAR accuracy and density. Acquisition dates and acreage are shown in Table 1, a complete list of contracted deliverables provided to PSLC.

In addition to these lidar point data, the bare earth Digital Elevation Models (DEM) created from the lidar point data are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

Provide high resolution surface elevation data from the Willapa River Valley Delivery 1 LiDAR dataset.

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A footprint of this data set may be viewed in Google Earth at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4956/supplemental/wa2014_pslc_willapa_delivery1_m4956.kmz

The final report for this project can be viewed at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4956/supplemental/wa2014_pslc_willapa_delivery1_m4956_lidarreport.pdf

LiDAR points in LAZ format (ASPRS Classes 1,2)

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Any conclusions drawn from the analysis of this information are not the responsibility

of Quantum Spatial, PSLC, NOAA, the Office for Coastal Management or its partners.

This data can be obtained on-line at the following URL:

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=4956;

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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be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions.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. These data depict the heights at the time of the survey and are only accurate for that time.

All discernible laser returns were processed for the output dataset. The discrepancy between native and delivered density will vary depending on terrain, land cover, and the prevalence of water bodies.

Ground survey points were collected using real time kinematic (RTK) and post-processed kinematic (PPK) survey techniques. A Trimble R7 base unit was positioned at a nearby monument to broadcast a kinematic correction to a roving Trimble R8 GNSS receiver. All GSP measurements were made during periods with a Position Dilution of Precision (PDOP) of less than 3.0 with at least six satellites in view of the stationary and roving receivers. When collecting RTK and PPK data, the rover records data while stationary for five seconds, then calculates the pseudorange position using at least three one-second epochs.; Quantitative Value: 0.02 meters, Test that produced the value: Relative errors for the position must be less than 1.5 cm horizontal and 2.0 cm vertical in order to be accepted.

The Root Mean Square Error (RMSE) of the vertical accuracy of delivery 1 is 0.125 ft. Please see the LiDAR data report for a discussion of the statistics related to this dataset.; Quantitative Value: 0.125 meters, Test that produced the value: Accuracy was assessed using 794 ground survey RTK (real time kinematic) and PPK (post processed kinematic) points.

LiDAR data has been collected and processed for all areas within the delivery 1 area.

All areas were surveyed with an opposing flight line side-lap of more than 50% (more than 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.

The NOAA Office for Coastal Management (OCM) downloaded topographic files in .laz format from PSLC's FTP site.