2012 USGS Lidar: Elwha River (WA)

TASK NAME: Elwha River, WA LiDAR

LiDAR Data Acquisition and Processing Production

Task USGS Contract No. G10PC00057

Task Order No. G11PD01088

Woolpert Order No. 71910

CONTRACTOR: Woolpert, Inc. LiDAR data is a remotely sensed high resolution elevation data collected by an airborne platform. The LiDAR sensor uses a combination of laser range finding, GPS positioning, and inertial measurement technologies. The LiDAR systems collect data point clouds that are used to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 1.0 meter. The final products include first, last, and at least one intermediate return LAS, full classified LAS and one (1) meter pixel raster DEMs of the bare-earth surface in ERDAS IMG Format.The task order consisted of approximately thirty-five (35) square mile area along the Elwha River in Washington. This data will be used to assist the Department of Interior with the Elwha River Restoration Project following the removal of the Elwha Dam. The LiDAR data was acquired on October 10, 15, 16, and 17, 2012.

This task order consisted of LiDAR data acquisition and processing for the USGS. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 1.0 meter. The LiDAR data was collected to meet a vertical accuracy requirement of 18.2cm (0.6 ft) at the 95% confidence level. The LiDAR data was provided in 1,000 meters x 1,000 meters tiles in the UTM projection. The LiDAR tile file name was derived from the southwest corner of each tile. The tiles were named based on the US National Grid. The LAS tiles were only renamed to add the acquisition date to the beginning of the file and alter the end of the filename to a sequential naming convention.

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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/geoid18/4955/supplemental/wa2012_usgs_elwha_river_m4955.kmz

A final lidar report can be found here:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4955/supplemental/wa2012_usgs_elwha_river_m4955_lidarreport.pdf

An accuracy assessment for the project may be viewed here:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/4955/supplemental/wa2012_usgs_elwha_river_m4955_surveyreport.pdf

LiDAR points in LAS format (ASPRS Classes 1,2,7,9,10,11)

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Any conclusions drawn from the analysis of this information are not the responsibility of Woolpert, USGS, 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=4955;

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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.

Horizontal accuracy is listed as +/- 3.8-foot at the 95% confidence level in delivered (original) metadata though is reported in the lidar report that horizontal accuracy has a relative error estimation of between 1 cm and 2 cm.; Quantitative Value: 0.02 meters, Test that produced the value: See project report, link available in the supplemental information above.

LAS data covering the Elwha River, Washington Lidar Task Order was compared to survey control points to determine the FVA of the LAS Swath and of the Bare-Earth DEM. In addition, this LAS data was compared to supplemental points from categories: Bare Earth Open Terrain, Tall Weeds/Crops, and Forested and Fully Grown. LAS Swath Fundamental Vertical Accuracy (FVA) Tested 0.152m (15.2cm) fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using 0.078m (7.8cm) (RMSE(z) x 1.96000 tested against the TIN. Bare-Earth DEM Fundamental Vertical Accuracy (FVA) Tested 0.162m (16.2cm) fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using 0.083m (8.3cm) (RMSE(z) x 1.96000 tested against the DEM.; Quantitative Value: 0.152 meters, Test that produced the value: LAS Swath Fundamental Vertical Accuracy (FVA) Tested 0.152 meters fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using RMSE(z) x 1.96000. This data set was tested against the TIN using independent check points.; Quantitative Value: 0.162 meters, Test that produced the value: Bare-Earth DEM Fundamental Vertical Accuracy (FVA) tested 0.162 meters fundamental vertical accuracy at a 95 percent confidence level, derived according to NSSDA, in open terrain using RMSE(z) x 1.96000. This data set was tested against the DEM using independent check points.; Quantitative Value: 0.143 meters, Test that produced the value: Bare Earth/Open Terrain Land Cover Classification Supplemental Vertical Accuracy (SVA) tested 0.143 meters supplemental vertical accuracy at the 95th percentile in Bare Earth/Open Terrain. Tested against the DEM. Errors larger than 95th percentile include:

Point 106, Easting 455555.814, Northing 5322326.745, Z-Error 0.144

Point 116, Easting 459096.817, Northing 5331529.004, Z-Error 0.148; Quantitative Value: 0.291 meters, Test that produced the value: The Tall Weeds/Crops Land Cover Classification Supplemental Vertical Accuracy (SVA) tested 0.291 meters supplemental vertical accuracy at the 95th percentile in Tall Weeds/Crops. Tested against the DEM. Tall Weeds/Crops errors larger than 95th percentile include:

Point 169, Easting 458866.554, Northing 5333118.706, Z-Error 0.293; Quantitative Value: 0.236 meters, Test that produced the value: The Forested and Fully Grown Land Cover Classification Supplemental Vertical Accuracy (SVA) tested 0.236 meters supplemental vertical accuracy at the 95th percentile in Forested and Fully Grown. Tested against the DEM. Forested and Fully Grown errors larger than 95th percentile include:

Point 233, Easting 459936.682, Northing 5328485.045, Z-Error 0.239; Quantitative Value: 0.258 meters, Test that produced the value: The Consolidated Vertical Accuracy (CVA) tested 0.258 meters consolidated vertical accuracy at the 95th percentile level, derived according to ASPRS Guidelines for Vertical Accuracy Reporting for LiDAR Data. This data set was tested against the DEM using independent check points. Based on the 95th percentile error in all land cover categories combined. Combined Land Cover Errors larger than 95 percent include:

Point 158, Easting 455941.88, Northing 5320597.031, Z-Error 0.263

Point 167, Easting 458742.638, Northing 5332568.325, Z-Error 0.266

Point 168, Easting 458751.388, Northing 5332562.195, Z-Error 0.291

Point 169, Easting 458866.554, Northing 5333118.706, Z-Error 0.293

Point 170, Easting 459282.631, Northing 5327659.036, Z-Error 0.340

The LiDAR data is visually inspected for completeness to ensure that are no gaps between flight lines.

All formatted data are validated using commercial GIS software to ensure proper formatting and loading prior to delivery.