2012 OLC Lidar: Baker Pass, Christmas Valley, Paulina Marsh, and Summer Lake, OR

Paulina Marsh

Summer Lake

Christmas Valley

Baker Pass

Oregon Military

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KMZ showing area of data coverage.

Data Report from the lidar contractor.

Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

Partial upload of Positional Accuracy fields only.

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Acquisition.

The LiDAR survey utilized a Leica ALS60 sensor mounted in a Cessna Caravan.The Leica system was set to acquire 88,000 laser pulses per second (i.e., 88 kHz pulse rate) and was flown at 1,100 meters above ground level (AGL), capturing a scan angle of ±15o from nadir. With these flight parameters, the laser swath width was 598m and the laser pulse footprint was 26cm. These settings were developed to yield points with an average native pulse density of 4 pulses per square meter over terrestrial surfaces.

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

Processing.

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 and thermal image 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. Data were then converted to orthometric elevations (NAVD88) by applying a Geoid03 correction.

Software: ALS Post Processing Software v.2.74

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.

Software: TerraScan v.12.004, TerraModeler v.12.002

The NOAA Office for Coastal Management (OCM) received the point cloud LAS files from DOGAMI. The files contained Lidar elevation and intensity measurements. The data were in NAD83(CORS96) UTM 10 or 11 meters coordinates and NAVD88 (Geoid03) vertical meters. OCM transformed the data to geographic coordinates and ellipsoid heights for ingest in the Digital Coast Data Access Viewer.

This metadata record was generated from the project report as no metadata record was received from DOGAMI.