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
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112

use num_traits::Float;
use std::iter::Sum;

use crate::{Line, LineString, MultiLineString};

/// Calculation of the length

pub trait EuclideanLength<T, RHS = Self> {
    /// Calculation of the length of a Line
    ///
    /// # Examples
    ///
    /// ```
    /// use geo::algorithm::euclidean_length::EuclideanLength;
    /// use geo::line_string;
    ///
    /// let line_string = line_string![
    ///     (x: 40.02f64, y: 116.34),
    ///     (x: 42.02f64, y: 116.34),
    /// ];
    ///
    /// assert_eq!(
    ///     2.,
    ///     line_string.euclidean_length(),
    /// )
    /// ```
    fn euclidean_length(&self) -> T;
}

impl<T> EuclideanLength<T> for Line<T>
where
    T: Float,
{
    fn euclidean_length(&self) -> T {
        ::geo_types::private_utils::line_euclidean_length(*self)
    }
}

impl<T> EuclideanLength<T> for LineString<T>
where
    T: Float + Sum,
{
    fn euclidean_length(&self) -> T {
        self.lines().map(|line| line.euclidean_length()).sum()
    }
}

impl<T> EuclideanLength<T> for MultiLineString<T>
where
    T: Float + Sum,
{
    fn euclidean_length(&self) -> T {
        self.0
            .iter()
            .fold(T::zero(), |total, line| total + line.euclidean_length())
    }
}

#[cfg(test)]
mod test {
    use crate::algorithm::euclidean_length::EuclideanLength;
    use crate::line_string;
    use crate::{Coordinate, Line, MultiLineString};

    #[test]
    fn empty_linestring_test() {
        let linestring = line_string![];
        assert_relative_eq!(0.0_f64, linestring.euclidean_length());
    }
    #[test]
    fn linestring_one_point_test() {
        let linestring = line_string![(x: 0., y: 0.)];
        assert_relative_eq!(0.0_f64, linestring.euclidean_length());
    }
    #[test]
    fn linestring_test() {
        let linestring = line_string![
            (x: 1., y: 1.),
            (x: 7., y: 1.),
            (x: 8., y: 1.),
            (x: 9., y: 1.),
            (x: 10., y: 1.),
            (x: 11., y: 1.)
        ];
        assert_relative_eq!(10.0_f64, linestring.euclidean_length());
    }
    #[test]
    fn multilinestring_test() {
        let mline = MultiLineString(vec![
            line_string![
                (x: 1., y: 0.),
                (x: 7., y: 0.),
                (x: 8., y: 0.),
                (x: 9., y: 0.),
                (x: 10., y: 0.),
                (x: 11., y: 0.)
            ],
            line_string![
                (x: 0., y: 0.),
                (x: 0., y: 5.)
            ],
        ]);
        assert_relative_eq!(15.0_f64, mline.euclidean_length());
    }
    #[test]
    fn line_test() {
        let line0 = Line::new(Coordinate { x: 0., y: 0. }, Coordinate { x: 0., y: 1. });
        let line1 = Line::new(Coordinate { x: 0., y: 0. }, Coordinate { x: 3., y: 4. });
        assert_relative_eq!(line0.euclidean_length(), 1.);
        assert_relative_eq!(line1.euclidean_length(), 5.);
    }
}