use_earth_constants/
lib.rs

1#![forbid(unsafe_code)]
2#![doc = include_str!("../README.md")]
3
4/// Approximate mean Earth radius, in meters.
5pub const EARTH_RADIUS_MEAN: f64 = 6_371_000.0;
6
7/// WGS84-defined equatorial Earth radius, in meters.
8pub const EARTH_RADIUS_EQUATORIAL: f64 = 6_378_137.0;
9
10/// WGS84-defined polar Earth radius, in meters.
11pub const EARTH_RADIUS_POLAR: f64 = 6_356_752.314_245;
12
13/// Approximate Earth mass, in kilograms.
14pub const EARTH_MASS: f64 = 5.972_2e24;
15
16/// Conventional standard gravity, in meters per second squared.
17pub const STANDARD_GRAVITY: f64 = 9.806_65;
18
19/// Conventional standard sea-level atmospheric pressure, in pascals.
20pub const SEA_LEVEL_STANDARD_PRESSURE: f64 = 101_325.0;
21
22/// WGS84-defined semi-major axis, in meters.
23pub const WGS84_A: f64 = 6_378_137.0;
24
25/// WGS84-defined semi-minor axis, in meters.
26pub const WGS84_B: f64 = 6_356_752.314_245;
27
28/// WGS84-defined flattening, dimensionless.
29pub const WGS84_FLATTENING: f64 = 1.0 / 298.257_223_563;
30
31#[cfg(test)]
32mod tests {
33    use super::{
34        EARTH_MASS, EARTH_RADIUS_EQUATORIAL, EARTH_RADIUS_MEAN, EARTH_RADIUS_POLAR,
35        SEA_LEVEL_STANDARD_PRESSURE, STANDARD_GRAVITY, WGS84_A, WGS84_B, WGS84_FLATTENING,
36    };
37
38    fn runtime(value: f64) -> f64 {
39        value
40    }
41
42    #[test]
43    fn earth_radii_follow_expected_ordering() {
44        assert!(runtime(EARTH_RADIUS_EQUATORIAL) > runtime(EARTH_RADIUS_MEAN));
45        assert!(runtime(EARTH_RADIUS_MEAN) > runtime(EARTH_RADIUS_POLAR));
46    }
47
48    #[test]
49    fn wgs84_axes_match_radius_aliases() {
50        assert_eq!(EARTH_RADIUS_EQUATORIAL, WGS84_A);
51        assert_eq!(EARTH_RADIUS_POLAR, WGS84_B);
52    }
53
54    #[test]
55    fn representative_environment_constants_are_reasonable() {
56        assert!(runtime(WGS84_FLATTENING) > 0.0);
57        assert!(runtime(STANDARD_GRAVITY) > 9.8 && runtime(STANDARD_GRAVITY) < 9.9);
58        assert_eq!(SEA_LEVEL_STANDARD_PRESSURE, 101_325.0);
59        assert!(runtime(EARTH_MASS) > 0.0);
60    }
61}
use_earth_constants/lib.rs

use_earth_constants/
lib.rs
