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...华盛顿州胡安·德富卡海峡沿岸朝向海的海岸陡崖面约2.0千米沿岸段的点云数据，是通过运动恢复结构（Structure-from-Motion, SfM）摄影测量法，基于2016至2022年间每季度至少采集一次的数码照片生成的。这些点云旨在评估陡崖面侵蚀与陡崖基部沉积的空间与时间分布模式。本次使用的照片取自Miller等人（2022）的研究，采用修改后的美国地质调查局（USGS）公开流程（Over等人，2022），结合Agisoft Metashape Professional 1.8.5软件完成配准。按照Wernette等人（2022）描述的四维方法，在单个数据块中完成照片配准，并通过重建不确定性（Reconstruction Uncertainty, Ru）和投影精度（Projection Accuracy, Pa）对稀疏点云进行滤波。针对每个测量日期，通过仅启用单张拍摄日期的相机，独立生成密集点云。该流程针对全部30个照片测量日期重复执行，得到……，陡崖照片的拍摄方式分为乘船拍摄或沿海滩步行拍摄（Miller等人，2022）。在可行情况下，照片通过独立的实时动态差分全球导航卫星系统（RTK GNSS）进行地理标记，但并非所有测量日期都具备GNSS地理定位信息。Miller等人（2022）的照片采用修改后的USGS公开流程（Over等人，2022），结合Agisoft Metashape Professional 1.8.5完成配准。所有30个测量日期的照片均按照Wernette等人（2022）提出的四维方法，以Over等人（2022）的默认参数在单个数据块中完成配准。对配准后的稀疏点云采用两步滤波流程，设置重建不确定性（Re）阈值为10，投影精度（Pa）阈值为3。随后生成超高精度且经过强滤波的密集点云。最后，依据点云置信度对点云进行滤波，剔除置信度为2及以下的点。暂无适用于所有点云的地面实测数据集…… # 华盛顿州埃尔瓦河河口附近基于运动恢复结构（SfM）生成的海岸陡崖点云数据集 [https://doi.org/10.5061/dryad.8pk0p2nww](https://doi.org/10.5061/dryad.8pk0p2nww) 该点云数据集可用于评估陡崖面侵蚀与陡崖基部沉积的分布模式。但由于照片相对于海滩的极端倾斜角度，海滩区域的重建效果普遍较差，若使用海滩点云开展研究或分析时需谨慎。 ## 数据与文件结构说明 点云数据及其关联的元数据纯文本文件按测量日期打包压缩，命名格式为：YYYYMMDD_。其中日期由4位年份、2位月份及2位日期组成。_指代照片拍摄的原始位置，分为"from_beach"（沿海滩步行拍摄陡崖照片）与"from_boat"（乘船拍摄）两类。标注"from_beach"的归档文件源自沿海滩步行拍摄的陡崖照片，标注"from_boat"的归档文件源自……