A method for calculating spiral swath paths in an area with irregular boundaries and providing automatic guidance of a vehicle along the calculated spiral swath paths. A baseline swath path is generated, and at least one adjacent swath path is calculated based on the minimum turning radius of the vehicle and associated implement. An algorithm calculates the continuous spiral swath path by monitoring a position data points at the end point of the previous swath path at the starting point of the at least one adjacent swath path, configuring a radius of curvature for each individual swath path determining the radius of curvature for each swath path and joining the individual swath paths into one continuous spiral swath path.