Data Management Plan

Watershed Sciences, Inc. (WSI) collected Light Detection and Ranging (LiDAR) data

on the Quinault River Basin survey area for the Puget Sound LiDAR Consortium and

the Quinault Indian Nation. Delivery 1 of the survey area was collected on April

16th, 29th, 30th, and May 1st, 2011 and delivered on June 14th, 2011. Delivery 2

of the survey area was collected on November 6th -19th, and December 1st - 4th,

2011. This report documents the data acquisition, processing methods, accuracy

assessment, and deliverables for the first 91,162 acres of Delivery 1 data and

the final 144,033 acres of Delivery 2 data for a total of 234,394 acres. The

requested area was expanded to include a 100m buffer to ensure complete coverage

and adequate point densities around survey area boundaries. The 2012 Quinault

River Basin data (Delivery 2) were integrated with overlapping portions of the

2011 data (Delivery 1) to provide seamless models.

Process Steps:

• Acquisition. The LiDAR survey utilized a Leica ALS50-II sensor in a Cessna Caravan 208B. Depending on acquisition day, weather, and terrain, the Leica systems were set to acquire 105,000 laser pulses per second (i.e.105 kHz pulse rate) and flown at 900 meters above ground level (AGL), capturing a scan angle of +/- 14 degrees from nadir. These settings were developed to yield points with an average native pulse density of 8 pulses per square meter over terrestrial surfaces. It is not uncommon for some types of surfaces to return fewer pulses than the laser originally emitted. These discrepancies between 'native' and 'delivered' density will vary depending on terrain, land cover, and the prevalence of water bodies. All areas were surveyed with an opposing flight line side-lap of more than 60% (less than 100% overlap) to reduce laser shadowing and increase surface laser painting. The Leica laser systems allow up to four range measurements (returns) per pulse, and all discernable laser returns were processed for the output dataset. To accurately solve for laser point position (geographic coordinates x, y, z) the positional coordinates of the airborne sensor and the attitude of the aircraft were recorded continuously throughout the LiDAR data collection mission. Aircraft position was measured twice per second (2 Hz) by an onboard differential GPS unit. 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/sensor position and attitude data are indexed by GPS time.
• 1. Resolved kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. Software - Waypoint GPS v.8.10, Trimble Business Center 2.6 2. Developed a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with attitude data. Sensor head position and attitude were calculated throughout the survey. The SBET data were used extensively for laser point processing. Software - IPAS TC v.3.1 3. Calculated laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Created raw laser point cloud data for the entire survey in *.las (ASPRS v. 1.2) format. Software - ALS Post Processing Software v.2.74, Corpscon 6 4. Imported raw laser points into manageable blocks (less than 500 MB) to perform manual relative accuracy calibration and filter for pits/birds. Ground points were then classified for individual flight lines (to be used for relative accuracy testing and calibration). Software - TerraScan v.12.004 5. Using ground classified points per each flight line, the relative accuracy was tested. Automated line-to-line calibrations were then performed for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calibrations were performed on ground classified points from paired flight lines. Every flight line was used for relative accuracy calibration. Software - TerraMatch v.12.001 6. Position and attitude data were imported. Resulting data were classified as ground and non-ground points. Statistical absolute accuracy was assessed via direct comparisons of ground classified points to ground RTK survey data. Data were then converted to orthometric elevations (NAVD88) by applying a Geoid03 correction. Software: TerraScan v.12.004, TerraModeler v.12.002 7. Bare Earth models were created as a triangulated surface and exported as ArcInfo ASCII grids at a 3-foot pixel resolution. Highest Hit models were created for any class at 3-foot grid spacing and exported as ArcInfo ASCII grids. Software - TerraScan v.12.004, ArcMap v.10.0, TerraModeler v.12.002
• 2013-12-04 00:00:00 - The NOAA Office for Coastal Management (OCM) downloaded topographic files in LAZ format from PSLC's website. The files contained lidar easting, northing, elevation, intensity, return number, class, scan angle and GPS time measurements; the data was received in state plane Washington (in feet) and vertical coordinates were referenced to NAVD88 in feet using the Geoid03 model. OCM performed the following processing for data storage and Digital Coast provisioning purposes: 1. The All-Return LAZ files were checked for bad elevations 2. The laz files were converted from a Projected Coordinate System (SP 4602) to a Geographic Coordinate system (NAD83) 3. The laz files were then converted to ellipsoidal vertical units in meters using the geoid03 conversion.

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

https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=2603

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