distance.rs

    // currently gives answer in meters
    fn haversine_distance(&self, p: &Point<T>) -> T {
        let R = 6373000;
        // issue is on the next line: Point<T> has a method .y() and a method
        // .x() and both return <T>, where T has the trait bounds
        // Float + ToPrimitive. But `to_radians` is not part of those trait
        // bounds and I'm not sure how to use the built-in function without
        // hardcoding or casting to f64 or f32
        let a = ((self.y() - p.y()).to_radians() / 2).sin().powi(2) +
              (((self.x() - p.x()).to_radians() / 2).sin().powi(2) *
               self.y().cos() * p.y().cos());
        R * 2 * a.sqrt().atan2((1 - a).sqrt())
    }

error.log

warning: unused manifest key: package.keyword
warning: unused manifest key: package.keyword
warning: unused manifest key: package.keyword
warning: unused manifest key: package.keyword
   Compiling geo v0.2.2 (file:///Users/tmcw/src/rust-geo)
src/algorithm/distance.rs:38:37: 38:47 error: no method named `to_radians` found for type `T` in the current scope
src/algorithm/distance.rs:38         let a = ((self.y() - p.y()).to_radians() / 2).sin().powi(2) +
                                                                 ^~~~~~~~~~
src/algorithm/distance.rs:38:37: 38:47 help: items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `to_radians`, perhaps you need to implement it:
src/algorithm/distance.rs:38:37: 38:47 help: candidate #1: `core::num::Float`
src/algorithm/distance.rs:39:36: 39:46 error: no method named `to_radians` found for type `T` in the current scope
src/algorithm/distance.rs:39               (((self.x() - p.x()).to_radians() / 2).sin().powi(2) *
                                                                ^~~~~~~~~~
src/algorithm/distance.rs:39:36: 39:46 help: items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `to_radians`, perhaps you need to implement it:
src/algorithm/distance.rs:39:36: 39:46 help: candidate #1: `core::num::Float`
error: aborting due to 2 previous errors
src/algorithm/distance.rs:38:37: 38:47 error: no method named `to_radians` found for type `T` in the current scope
src/algorithm/distance.rs:38         let a = ((self.y() - p.y()).to_radians() / 2).sin().powi(2) +
                                                                 ^~~~~~~~~~
src/algorithm/distance.rs:38:37: 38:47 help: items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `to_radians`, perhaps you need to implement it:
src/algorithm/distance.rs:38:37: 38:47 help: candidate #1: `core::num::Float`
src/algorithm/distance.rs:39:36: 39:46 error: no method named `to_radians` found for type `T` in the current scope
src/algorithm/distance.rs:39               (((self.x() - p.x()).to_radians() / 2).sin().powi(2) *
                                                                ^~~~~~~~~~
src/algorithm/distance.rs:39:36: 39:46 help: items from traits can only be used if the trait is implemented and in scope; the following trait defines an item `to_radians`, perhaps you need to implement it:
src/algorithm/distance.rs:39:36: 39:46 help: candidate #1: `core::num::Float`
error: aborting due to 2 previous errors
error: Could not compile `geo`.

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