Coastal bluff point clouds derived from SfM near Elwha River mouth, Washington from 2016-04-18 to 2020-05-08

Point Clouds of an approximately 2.0 km alongshore reach of seaward-facing coastal bluff faces on the Strait of Juan de Fuca, Washington State, were derived using structure-from-motion (SfM) photogrammetry from digital photos collected at least quarterly between 2016 and 2022. The point clouds were derived to assess spatial and temporal patterns of erosion on the bluff face and deposition at the base of the bluff. Photos from Miller, et al. (2022) were aligned using a modified USGS published workflow (Over, et al., 2022) with Agisoft Metashape Professional 1.8.5. Photos were aligned within a single chunk in a 4D approach described by Wernette, et al. (2022), and the sparse point cloud was filtered by reconstruction uncertainty (Ru) and projection accuracy (Pa). Dense point clouds were generated independently for each survey date by disabling all cameras except for a single photo date and then generating the dense cloud. This was repeated for each of the 30 photo survey dates, resulting ..., Photos of the bluff were taken from a boat or while walking along the beach (Miller, et al., 2022). Where possible, photos were geotagged with information from a stand-alone RTK GNSS, although not all survey dates had GNSS geolocation information. Photos from Miller, et al. (2022) were aligned using the USGS published workflow (Over, et al., 2022) with Agisoft Metashape Professional 1.8.5. All photos from all 30 survey dates were aligned within a single chunk in a 4D approach described by Wernette, et al. (2022) with the default parameters of Over, et al., (2022). A two-step filtering process was applied to the aligned sparse point clouds, with a reconstruction uncertainty (Re) value of 10 and a projection accuracy (Pa) of 3. Dense point clouds were then generated with ultra-high quality and aggressive filtering. Finally, point clouds were filtered by their point confidence to eliminate points with a confidence of 2 or lower.
No ground-truth dataset was available for any of the point cl..., , # Coastal bluff point clouds derived from SfM near Elwha River mouth, Washington

[https://doi.org/10.5061/dryad.8pk0p2nww](https://doi.org/10.5061/dryad.8pk0p2nww)

These point clouds may be useful for evaluating patterns of erosion on the bluff face and deposition at the base of the bluff. However, because of the extreme obliquity of the photos relative to the beach, reconstruction of the beach was generally poor, and caution should be used if using the beach points for research or analysis.

## Description of the data and file structure

Point clouds and their associated metadata plain text file are zipped by survey date with the following format: YYYYMMDD_. Dates are represented by 4-digit year, 2-digit month, and 2-digit day. refers to the original locations the photos were taken from, either “from_beach” or “from_boat”. Archives tagged with “from_beach” were derived from photos of the bluff taken while walking along the beach, and archives tagged with “from_boat” were derived fro...