2020 USFS Lidar DEM: Sycan Marsh, OR

Acquisition dates based on tile filenames.

Custom download of data allowing subsetting and change of projection

Bulk download of tiles.

Data report from the lidar acquisition contractor. This does not reflect processing done by NOAA OCM.

KMZ showing the area covered by the data.

LiDAR and imagery acquisition for the Sycan USFS R6 project was performed with an Optech Galaxy PRIME LiDAR sensor. The LiDAR sensor was placed in a customized mount to minimize error and increase accuracy. Aero-Graphics flew at an approximate altitude of 5,249 ft above ground level (AGL) and made appropriate adjustments to compensate for topographic relief over the project’s over 71 flightlines. LiDAR acquisition was planned with 60% side overlap and an aggregate point density of 8 points per square meter throughout the project area. The settings used for collection consisted of a pulse rate frequency (PRF) of 400 kHz, a scan frequency of 67.5 Hz, and a scan angle of +/- 20 degrees from the nadir position (full scan angle 40 degrees).

The absolute sensor calibration was adjusted for the difference in roll, pitch, heading, and scale between the raw laser point cloud from the sensor and surveyed control points on the ground.

Differentially corrected the 1/5-second airborne GPS positions with ground base station; combined and refined the GPS positions with 1/200-second IMU (roll-pitch-yaw) data through development of a smoothed best estimate of trajectory (SBET).

SBET was combined with raw LiDAR range data and solved for real-world position for each laser point. Point cloud data was produced by flight strip in ASPRS v1.4 .LAS format and output in the local coordinate system.

Relative calibration was performed by correcting for roll, pitch, heading, and scale discrepancies between adjacent flightlines and the results were tested for accuracy.

Data was cut into project-specified tiles and grossly long and short returns were filtered out.

Classification algorithms were run on points in each tile, separating them into bare earth and unclassified points. Manually corrected areas that were not completely classified by the automated algorithms.

Data were received by NOAA Office for Coastal Management from the U.S. Forest Service in USFS region 6 Albers coordinates. Data were ingested into the Data Access Viewer system after reformatting to cloud optimized geotiffs.