2008 USFS Lidar: Sherman Pass, Colville NF, WA

Initial collection

collection to fill gaps

Custom download allowing user selection of area, projection, format, etc.

Bulk download of files. These are in orthometric NAVD88 vertical datum.

Data report from the contractor. Represents the data as delivered to USFS. Modifications have occurred to the data, as noted in this metadata.

The LiDAR survey utilized a Leica ALS50 Phase II sensor mounted in a Cessna Caravan 208B. The Leica ALS50 Phase II system was set to acquire greater than 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 (see Table 2.1). These settings are developed to yield points with an average native pulse density of 8 points per square meter over terrestrial surfaces. Some types of surfaces (i.e., dense vegetation or water) may return fewer pulses than the laser originally emitted. Therefore, the delivered density can be less than the native density and vary according to distributions of terrain, land cover, and water bodies.

The study area was surveyed with opposing flight line side-lap of at least 50% (100% overlap) to reduce laser shadowing and increase surface laser painting. The system allows up to four range measurements per pulse, and all discernable laser returns were processed for the output dataset.

Point cloud data were classified for ground points by Watershed Sciences. Ground points were given a point class of two (2) as specified by the LAS 1.1 format. Unclassified points were given a class of one (1).

Classified point clouds were received by NOAA from US Forest Service in Washington State Plane North NAD83(HARN), NAVD88/Geoid03. For ingest into the Digital Coast Data Access Viewer, the data were converted to geographic coordinates and the geoid model was removed.