geo/algorithm/
vincenty_length.rs

1use num_traits::FromPrimitive;
2
3use crate::vincenty_distance::{FailedToConvergeError, VincentyDistance};
4use crate::{CoordFloat, Line, LineString, MultiLineString};
5
6/// Determine the length of a geometry using [Vincenty’s formulae].
7///
8/// [Vincenty’s formulae]: https://en.wikipedia.org/wiki/Vincenty%27s_formulae
9pub trait VincentyLength<T, RHS = Self> {
10    /// Determine the length of a geometry using [Vincenty’s formulae].
11    ///
12    /// # Units
13    ///
14    /// - return value: meters
15    ///
16    /// # Examples
17    ///
18    /// ```
19    /// use geo::prelude::*;
20    /// use geo::LineString;
21    ///
22    /// let linestring = LineString::<f64>::from(vec![
23    ///     // New York City
24    ///     (-74.006, 40.7128),
25    ///     // London
26    ///     (-0.1278, 51.5074),
27    ///     // Osaka
28    ///     (135.5244559, 34.687455)
29    /// ]);
30    ///
31    /// let length = linestring.vincenty_length().unwrap();
32    ///
33    /// assert_eq!(
34    ///     15_109_158., // meters
35    ///     length.round()
36    /// );
37    /// ```
38    ///
39    /// [Vincenty’s formulae]: https://en.wikipedia.org/wiki/Vincenty%27s_formulae
40    fn vincenty_length(&self) -> Result<T, FailedToConvergeError>;
41}
42
43impl<T> VincentyLength<T> for Line<T>
44where
45    T: CoordFloat + FromPrimitive,
46{
47    /// The units of the returned value is meters.
48    fn vincenty_length(&self) -> Result<T, FailedToConvergeError> {
49        let (start, end) = self.points();
50        start.vincenty_distance(&end)
51    }
52}
53
54impl<T> VincentyLength<T> for LineString<T>
55where
56    T: CoordFloat + FromPrimitive,
57{
58    fn vincenty_length(&self) -> Result<T, FailedToConvergeError> {
59        let mut length = T::zero();
60        for line in self.lines() {
61            length = length + line.vincenty_length()?;
62        }
63        Ok(length)
64    }
65}
66
67impl<T> VincentyLength<T> for MultiLineString<T>
68where
69    T: CoordFloat + FromPrimitive,
70{
71    fn vincenty_length(&self) -> Result<T, FailedToConvergeError> {
72        let mut length = T::zero();
73        for line_string in &self.0 {
74            length = length + line_string.vincenty_length()?;
75        }
76        Ok(length)
77    }
78}
geo/algorithm/vincenty_length.rs

geo/algorithm/
vincenty_length.rs
