This data was kindly shared by Sarah Kollar at the Ocean Conservancy.
Clean Swell is a cell phone app used by volunteers to track trash during cleanups. The app was created by the Ocean Conservancy. The app tracks the users location while they are conducting the cleanup to trace the line they walk. While they are cleaning up, they log the trash they see and the results for the cleanup are aggregated to the line.
GPS line data is in KML format in the spreadsheet (the raw data). This data was converted to a shapefile by Win Cowger.
More information about Clean Swell app and program: https://oceanconservancy.org/trash-free-seas/international-coastal-cleanup/cleanswell/
Details on data collection methodology is in the attached document "OC-Clean-Swell-Poster-form.pdf"