Fast geodesic distance approximations via flat surface projection

The FlatProjection struct can by used to project geographical coordinates from WGS84 into a cartesian coordinate system. In the projected form approximated distance and bearing calculations can be performed much faster than on a sphere. The precision of these calculations is very precise for distances up to about 500 km.

extern crate flat_projection;

use flat_projection::FlatProjection;

fn main() {
    let (lon1, lat1) = (6.186389, 50.823194);
    let (lon2, lat2) = (6.953333, 51.301389);

    let proj = FlatProjection::new(51.05);

    let p1 = proj.project(lon1, lat1);
    let p2 = proj.project(lon2, lat2);

    let distance = p1.distance(&p2);
    // -> 75.648 km
}

$ cargo bench

distance/flat           time:   [22.727 ns 22.955 ns 23.196 ns]
distance/haversine      time:   [63.349 ns 64.046 ns 64.787 ns]
distance/vincenty       time:   [358.10 ns 363.16 ns 369.46 ns]

According to these results the flat surface approximation is about 3x faster than the Haversine formula.

• cheap-ruler – Similar calculations in JavaScripts
• cheap-ruler-cpp – C++ port of cheap-ruler

This project is released under the MIT license.