CoastSeg: estimate of zone of potential shoreline change, California and southeast USA Atlantic (FL, GA, SC, NC), in geoJSON format. Data have been made by Daniel Buscombe, Marda Science. Data cover the shorelines of five states A single geoJSON file per region. Data outline the extent of potential shoreline change. A 30-m vector defining the average shoreline, and a 30-m vector defining the limit of erodible material, were constructed and merged, then buffered, and manually edited. It is designed to be used in conjunction with the program CoastSeg https://github.com/Doodleverse/CoastSeg , for masking shoreline estimates outside of reasonable spatial bounds.