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  4. Data Release 10.5066/P13FEC44

Topographic point clouds and change analysis for the Big Sur, California coastline from structure-from-motion photogrammetry from aerial photographs, 2017–2023

By Helen Willemien Dow, Jonathan A. Warrick, and Andrew C. Ritchie

https://doi.org/10.5066/P13FEC44

Dates

Published: Sept. 3, 2025

Summary

This data release presents structure-from-motion (SfM) products derived from aerial imagery collected along the California coast as part of an ongoing effort by the USGS Coastal and Marine Hazards and Resources Program (CMHRP) Remote Sensing Coastal Change (RSCC) project. The products presented herein are point cloud and change detection products for 33 flights between January 2017 to June 2023 focusing on ~13 km of seacliffs along the Big Sur coast from Anderson Canyon to Gorda Point. The point clouds were referenced to previously published lidar data and contain RGB information as well as XYZ. The change detection products were created using the Multiscale Model-to-Model Cloud Comparison (M3C2) tool and contain XYZ data, M3C2 output (distance, distance uncertainty, and significance), and a vegetation index (Visible Atmospherically Resistant Index, VARI) that was used to filter vegetation related noise from the M3C2 point clouds. All point cloud coordinates are in NAD83 UTM Zone 10 meters.

Location-Elevation Data

  • Structure-from-motion point clouds of an approximately 13 km long section of the Big Sur coast, California for 33 flights between 2017-01-25 and 2023-06-08

    Presented here are point clouds derived from aerial photography collected by the U.S. Geological Survey (USGS) using an oblique plane-mounted camera system, covering approximately 13 km of the coastline near Big Sur, California. These point clouds are referenced to previously published lidar data and contain RGB information as well as XYZ. Point cloud coordinates are in NAD83 UTM Zone 10 meters. Imagery was collected with a Nikon D800 camera in RAW format and processed using structure-from-motion photogrammetry with Agisoft PhotoScan version 1.7 through 2.0. Point clouds were clipped to an area of interest (AOI) using LASTools. The AOI was created in ArcGIS Pro 3.3.1.

  • Point clouds showing erosion in an approximately 13 km long section of the Big Sur coast, California, between two flights and projected onto topography from the second flight

    Presented here are point clouds of approximately 13 km of the Big Sur coastline each showing erosion (as positive values) between two dates. The point cloud coordinates reflect topography at the later date. Change detection was computed using point clouds published in this data release and developed with structure-from-motion on aerial photography collected by the U.S. Geological Survey (USGS) using an oblique plane-mounted camera system. Ground points were identified in these point clouds using LAStools and manual reclassification of some protruding rocks as ground. Non-ground points were then removed, and the point clouds were clipped to an area of interest (AOI) of the cliff face using LASTools. We used the Multiscale Model-to-Model Cloud Comparison (M3C2) tool to calculate change in the cliff face between two flights. The M3C2 point cloud is a subsampled (at 0.25-m resolution) version of the point cloud of the second flight and M3C2 distances reflect erosion that occurred between the previous flight and this flight. This point cloud was then filtered using a combination of the Visible Atmospherically Resistant Index (VARI) and manual assessment to eliminate changes that do not reflect erosion, such as vegetation changes. It was then additionally filtered to include only points that the M3C2 algorithm considered significant (low uncertainty). Point cloud contains XYZ data and the following scalar fields: G-R/G+R-B (VARI), M3C2 distance, distance uncertainty, and significant change. Point cloud coordinates are in NAD83 UTM Zone 10 meters. The AOI was created in ArcGIS Pro 3.3.1. M3C2 distances, VARI calculation, and filtering were calculated in CloudCompare v2.12.4. Note that some flight dates represented in the topographic point cloud dataset will not have an associated M3C2 file because the product showed no erosion but substantial vegetation noise and was thus excluded.

    Data Files

    BigSur_M3C2_PointClouds.zip - 514.8 MB

    Metadata Files

    BigSur_M3C2_metadata.xml - 19.7 KB

    BigSur_M3C2_metadata.txt - 19.4 KB

  • Synthetic ground control point locations used in photogrammetric processing of approximately 13 km of Big Sur coast from McWay Canyon to Gorda Point, 2017–2023

    This portion of the data release presents locations for the synthetic ground control points (SGCPs) used during the structure-for-motion alignment process in Agisoft Metashape v1.7-2.0. The locations were chosen from lidar flown in early 2018 and then tagged in all imagery where they could be found. Following this procedure the alignment was reoptimized prior to development of the dense point clouds presented in this data release. The data contain the easting, northing, and elevation of the SGCPs taken from the lidar, as well as a description of each location. The data are presented in a comma-delimited text file.

    Data Files

    BigSur_SGCP_locations.csv - 342 bytes

    Metadata Files

    BigSur_SGCP_locations_metadata.xml - 17.2 KB

    BigSur_SGCP_locations_metadata.txt - 16.7 KB

Suggested Citation

Dow, H.W., Warrick, J.A., and Ritchie, A.C., 2025, Topographic point clouds and change analysis for the Big Sur, California coastline from structure-from-motion photogrammetry from aerial photographs, 2017–2023: U.S. Geological Survey data release, https://doi.org/10.5066/P13FEC44

Overview Image

Overview image of data release