Simple distance along a route calculator. Given a set of waypoints, and ship positions, calculate the distance along the line (from first waypoint) and distance across track.
import waypoint_distance as wd
along, across = wd.get_simple_distance(wplons, wplats, shiplon, shiplat, central_lat=50.0)
Note the calculation is for small geographic areas where a Cartesian projection is valid. i.e. we are not taking into account changing dx with latitude.