Title:
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
Abstract:
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.
Supplemental_Information:
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Although this Federal Geographic Data Committee-compliant metadata file is intended to document the dataset in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology.
