AL/GA border point corrections

[ajfroggie]

A comprehensive review of AL/GA border points with corrections made where needed. Along the Chattahoochie River, points were generally aligned with the western river bank, as the border definition here is the average water mark along the western bank. North of the river, points were aligned with where signage and pavement changes take place, which was often a different location than where OSM labels the boundary. Past precedent for some routes along the AL/GA border was to mark at the signage/pavement change (an example being US 411 which was not changed for this update).