2015 OLC Topobathy Lidar: Middle Fork Willamette River, OR

Area includes the Middle Fork, Wilamette River and a buffer of land around it.

Collection dates of lidar

Application to create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base.

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document.

Report by WSI that formed the basis for this metadata. Contains additional information.

graphic showing the extent of the data set.

Planning:

The airborne survey was designed to collect a point density of 4-5 pulses/m2 for the topo-bathymetric LiDAR. The flight was planned with a scan angle of ±20o and 50% side-lap. The 50% side-lap was used to ensure uniform coverage and to minimize laser shadowing due to vegetation and terrain. The flights were conducted in the late fall during base flow conditions to maximize water clarity and ensure shallow depths.

The flight lines were developed using ALTM-NAV Planner (v.3.0) software and Leica Mission Pro Flight Planning and Evaluation (FPES) software. Efforts were taken to optimize flight paths by minimizing flight times while meeting all accuracy specifications. The WSI acquisition staff considered all factors such as air space restrictions, private property access, and GPS quality in the planning of this mission.

Lidar Survey:

The LiDAR survey was accomplished using a Leica ALS80 system dually mounted with a Riegl VQ-820-G topobathymetric sensor in a Cessna Caravan. The Riegl VQ-820-G uses a green wavelength (ʎ=532 nm) laser that is capable of collecting high resolution vegetation and topography data, as well as penetrating the water surface with minimal spectral absorption by water. The recorded waveform enables range measurements for all discernible targets for a given pulse. The Leica ALS80 laser system can record unlimited range measurements (returns) per pulse. It is not uncommon for some types of surfaces (e.g., dense vegetation or water) to return fewer pulses to the LiDAR sensor than the laser originally emitted. The discrepancy between first return and overall delivered density will vary depending on terrain, land cover, and the prevalence of water bodies. All discernible laser returns were processed for the output dataset. Table 3 (dataset report) summarizes the settings used to yield an average pulse densityof ≥4.0 points/m2 for green LiDAR returns, and ≥8.0 points/m2 for NIR LiDAR returns over the Middle Fork Willamette River project area.

Lidar Processing:

Upon completion of data acquisition, QSI processing staff initiated a suite of automated and manual techniques to process the data into the requested deliverables. Processing tasks included GPS control computations, smoothed best estimate trajectory (SBET) calculations, kinematic corrections, calculation of laser point position, sensor and data calibration for optimal relative and absolute accuracy, and LiDAR point classification (Table 7). Riegl’s RiProcess software was used to facilitate bathymetric return processing. Once bathymetric points were differentiated, they were spatially corrected for refraction through the water column based on the angle of incidence of the laser. QSI refracted water column points using QSI’s proprietary LAS processing software, LAS Monkey. The resulting point cloud data were classified using both manual and automated techniques. Processing methodologies were tailored for the landscape.

The NOAA Office for Coastal Management received the lidar data from the Oregon Lidar Consortium.

Data were received in NAD83(2011) UTM zone 10 meters with vertical coordinates in NAVD88(GEOID 12A) meters. They were converted to geographic coordinates and ellipsoid heights for ingestion.

Metadata was not delivered with the data. This metadata was created from the WSI report.