1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74
use crate::algorithm::geodesic_distance::GeodesicDistance; use crate::{Line, LineString, MultiLineString}; /// Determine the length of a geometry on an ellipsoidal model of the earth. /// /// This uses the geodesic measurement methods given by [Karney (2013)]. As opposed to older methods /// like Vincenty, this method is accurate to a few nanometers and always converges. /// /// [Karney (2013)]: https://arxiv.org/pdf/1109.4448.pdf pub trait GeodesicLength<T, RHS = Self> { /// Determine the length of a geometry on an ellipsoidal model of the earth. /// /// This uses the geodesic measurement methods given by [Karney (2013)]. As opposed to older methods /// like Vincenty, this method is accurate to a few nanometers and always converges. /// /// /// # Units /// /// - return value: meters /// /// # Examples /// /// ``` /// use geo::prelude::*; /// use geo::LineString; /// /// let linestring = LineString::<f64>::from(vec![ /// // New York City /// (-74.006, 40.7128), /// // London /// (-0.1278, 51.5074), /// // Osaka /// (135.5244559, 34.687455) /// ]); /// /// let length = linestring.geodesic_length(); /// /// assert_eq!( /// 15_109_158., // meters /// length.round() /// ); /// ``` /// /// [Karney (2013)]: https://arxiv.org/pdf/1109.4448.pdf fn geodesic_length(&self) -> T; } impl GeodesicLength<f64> for Line<f64> { /// The units of the returned value is meters. fn geodesic_length(&self) -> f64 { let (start, end) = self.points(); start.geodesic_distance(&end) } } impl GeodesicLength<f64> for LineString<f64> { fn geodesic_length(&self) -> f64 { let mut length = 0.0; for line in self.lines() { length = length + line.geodesic_length(); } length } } impl GeodesicLength<f64> for MultiLineString<f64> { fn geodesic_length(&self) -> f64 { let mut length = 0.0; for line_string in &self.0 { length = length + line_string.geodesic_length(); } length } }