2005 South Slough NERR Lidar DEM: Coos Bay, OR

Date of lidar collection.

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Link to dataset report.

This graphic displays the footprint for this lidar DEM data set.

Acquisition.

The LiDAR data was collected during September 2005. An Optech 3100 LiDAR system was mounted in a fixed-wing aircraft and flown 1,100 meters above ground level (AGL). A pulse repetition frequency (PRF) of 71 kHz with at least 100% overlap (minimum 50% side-lap) was used. Greater than 4 points per square meter and near nadir scan angles were used to increase penetration of vegetation to ground surfaces. Ground level GPS and aircraft IMU were collected during the flight.

Processing.

1. Flight lines and data were reviewed to ensure complete coverage of the study area and positional accuracy of the laser points.

2. Laser point return coordinates were computed using the REALM survey suite and PosPac based on independent data from the LiDAR system, IMU, and aircraft.

3. The raw LiDAR file was assembled into flight lines per return with each point having an associated x, y, and z coordinate.

4. Visual inspection of swath to swath laser point consistencies within the study area were used to perform manual refinements of system alignment.

5. Custom algorithms were designed to evaluate points between adjacent flight lines. Automated system alignment was computed based upon randomly selected swath to swath accuracy measurements that consider elevation, slope, and intensities. Specifically, refinement in the combination of system pitch, roll and yaw offset parameters optimize internal consistency.

6. Noise (e.g., pits and birds) was filtered using REALM software tools based on known elevation ranges and included the removal of any cycle slips.

7. Using TerraScan and Microstation, ground classifications utilized custom settings appropriate to the study area.

8. The corrected and filtered return points were compared to the RTK ground survey points collected to verify the vertical and horizontal accuracies.

9. Points were broken into processing bins and output areas and output as laser points, TINed and GRIDed surfaces.

The NOAA Office for Coastal Management (OCM) received 1 raster DEM file in ESRI ArcGrid format from DOGAMI. The data were in UTM Zone 10 (NAD83 HARN) coordinates and NAVD88 (Geoid03) elevations in meters. The bare earth raster files were at a 1 m grid spacing.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. Used internal script to assign the EPSG codes (Horiz - 3740, Vert - 5703) and convert to GeoTiff format.

2. Copied the files to https.