Key:coastline:survey quality
From OpenStreetMap Wiki
The survey quality of the coastline varies, and depending on the usage of the map, various forms of rendering might be applicable. coastline:survey_quality=complete and coastline:survey_quality=inadequate might be used to indicate quality of the survey. Where coastline are traced from high-res photos one can assume quality is complete. Where it is known that the data source are weak one should use inadequate so that maps requiring high coastline accuracy can be rendered with a warning about the quality of data. See INT 1 for example of usage.
Usage info
The coastline:survey_quality key usage:
