I'm trying to extract the coastline from a series of historic (hand drawn!) maps (I got the idea from NOAA). The maps are all scanned, rasterized (.tif files), georeferenced and correctly projected (NAD 1983), but I'm not sure what to do next!
Essentially all I want from the maps is the division between land and water, I can discard all other information. I was thinking I'd begin with a classification, but that's just a guess and I don't even know if it will work with these sorts of files. I also saw something about an indicator raster. Any and all advice would be appreciated! Thanks.