Ground control point locations for UAS surveys of the beaches at Fort Stevens State Park, OR, and Cape Disappointment State Park, WA, July 2021

This portion of the data release presents the locations of the temporary ground control points (GCPs) used for the structure-from-motion (SfM) processing of the imagery collected during the July 2021 unoccupied aerial system (UAS) surveys of the ocean beach at Fort Stevens State Park, OR, and Benson Beach at Cape Disappointment State Park, WA. Eighteen temporary ground control points (GCPs) were distributed throughout the survey area to establish survey control. The GCPs consisted of a combination of small square tarps with black-and-white cross patterns and "X" marks placed on the ground using temporary chalk. The GCP positions were measured using dual-frequency post-processed kinematic (PPK) GPS with corrections referenced to a static base station operating nearby. The GCP positions are presented in a comma-delimited text file.