Google Coordinates to Athens GA State Plane Converter

Athens engineering and GIS work largely standardized on Georgia State Plane West in feet, which corresponds to NAD83 / Georgia West (ftUS), EPSG:2240. Clarke County is inside that zone, so it became the default local grid for plans, survey deliverables, and CAD drawings. This choice did not appear randomly. State Plane is a long running U.S. surveying standard and Georgia formalized statewide East and West State Plane zones as a practical way to keep coordinates consistent across public projects and private design work.

Even though Civil 3D and most deliverables show coordinates in feet, a lot of the math under the hood is effectively metric. The ellipsoid parameters and datum definitions are expressed in meters, and most projection algorithms are implemented in meters first because that is how the geodetic constants are defined. The software then converts the final easting and northing into US survey feet for display and for construction friendly deliverables. That is why you can think of the workflow as a metric engine with an imperial output. It starts with latitude and longitude, goes through a datum and projection computation in a metric based geodetic model, and only at the end applies the unit conversion so you get feet that match local CAD standards.