Structure-from-Motion bathymetric maps from the Florida Keys, 2019

Structure-from-Motion Processing: the complete photo sets of each study area were subsampled such that minimum GPS spacing between the center camera location per collection instance was at least 0.75 m. For each survey site, the subsampled photo quintets were combined with GPS positions and camera-to-GPS-antennae distance vectors (lever arm offsets) and aligned with independent lens models for each camera. The computed camera positions and lens models were then refined using three statistical tools (reconstruction uncertainty, projection accuracy, and reprojection error) in Metashape to eliminate poorly constructed tie points. With trial and error, we found that threshold values of 20, 8 and 0.4 for these statistical tools, respectively, resulted in good alignment and adequately dense tie point distributions in both complex reef settings and simple sandy areas. Once the photo alignment and lens models were optimized, dense point clouds were generated with Metashape using the high point density and moderate filtering settings. The dense point clouds were used in Metashape to generate digital surface models at 1 cm resolution of each study area in TIFF file format.

Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed.

Corrected working URL links to cmgds data repository to the actual published links