geographiclib-rs

在 Rust 中实现 geographiclib 的一个子集。

文档

目前，它实现了直接和反地球测线计算。

如果您正在寻找 Rust 对 Karney 的 C++ 实现 的绑定，请参阅 https://crates.io/geographiclib。

示例

// Determine the point 10000 km NE of JFK - the "direct" geodesic calculation.
use geographiclib_rs::{Geodesic, DirectGeodesic};

let g = Geodesic::wgs84();
let jfk_lat = 40.64;
let jfk_lon = -73.78;
let northeast_azimuth = 45.0;

let (lat, lon, az) = g.direct(jfk_lat, jfk_lon, northeast_azimuth, 10e6);

use approx::assert_relative_eq;
assert_relative_eq!(lat, 32.621100463725796);
assert_relative_eq!(lon, 49.05248709295982);
assert_relative_eq!(az,  140.4059858768007);

// Determine the distance between two points - the "inverse" geodesic calculation.
use geographiclib_rs::{Geodesic, InverseGeodesic};

let g = Geodesic::wgs84();
let p1 = (34.095925, -118.2884237);
let p2 = (59.4323439, 24.7341649);
let s12: f64 = g.inverse(p1.0, p1.1, p2.0, p2.1);

use approx::assert_relative_eq;
assert_relative_eq!(s12, 9094718.72751138);

// Determine the perimeter and area of a polygon.
use geographiclib_rs::{Geodesic, PolygonArea, Winding};

let g = Geodesic::wgs84();
let mut pa = PolygonArea::new(&g, Winding::CounterClockwise);
pa.add_point(0.0, 0.0);
pa.add_point(0.0, 1.0);
pa.add_point(1.0, 1.0);
pa.add_point(1.0, 0.0);

let (perimeter_m, area_m_squared, num_points) = pa.compute(false);

use approx::assert_relative_eq;
assert_relative_eq!(perimeter_m, 443770.91724830196);
assert_relative_eq!(area_m_squared, 12308778361.469452);
assert_eq!(num_points, 4);

// Determine the distance between rovers Pathfinder and Curiosity on Mars
use geographiclib_rs::{Geodesic, InverseGeodesic};

let mars = Geodesic::new(3396190.0, 1.0 / 169.8944472);
let pathfinder = (19.26, 326.75);
let curiosity = (-4.765700445, 137.39820983);
let distance_m: f64 = mars.inverse(curiosity.0, curiosity.1, pathfinder.0, pathfinder.1);

assert_eq!(distance_m.round(), 9639113.0);

功能

1. accurate：默认启用。使用 accurate crate 在 PolygonArea 中提供高精度的多边形面积和周长。可以禁用以提高性能或当不使用 PolygonArea 时。

基准测试

要比较直接和反地球测线计算与 geographiclib c 绑定，运行

cargo bench

这将产生如下输出

direct (c wrapper)/default
                        time:   [24.046 µs 24.071 µs 24.099 µs]

direct (rust impl)/default
                        time:   [26.129 µs 26.168 µs 26.211 µs]

inverse (c wrapper)/default
                        time:   [45.061 µs 45.141 µs 45.227 µs]

inverse (rust impl)/default
                        time:   [67.739 µs 67.796 µs 67.865 µs]

表明，至少在这个基准测试中，Rust 实现比 C 绑定慢 10-50%。