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Mercurial > core / rust/lib/obj/src/object/location.rs

changeset 698: 96958d3eb5b0
parent: 3d78bed56188
author: Richard Westhaver <ellis@rwest.io>
date: Fri, 04 Oct 2024 22:04:59 -0400
permissions: -rw-r--r--
description: fixes 
     1 //! obj::location
     2 //!
     3 //! Location object types
     4 use crate::Objective;
     5 
     6 use serde::{Deserialize, Serialize};
     7 
     8 /// A City object descriptor. Serves as an anchor for many properties
     9 /// in location-based data.
    10 #[derive(Serialize, Deserialize, Debug)]
    11 pub struct City {
    12   point: Point,
    13   name: String,
    14   area: Option<Vec<Point>>,
    15   region: Option<String>,
    16   state: Option<String>,
    17   country: Option<String>,
    18   timezone: Option<String>,
    19 }
    20 
    21 impl City {
    22   pub fn new(point: Point) -> Self {
    23     City {
    24       point,
    25       name: "ellisville".to_string(),
    26       area: None,
    27       region: None,
    28       country: None,
    29       state: None,
    30       timezone: Some("est".to_string()),
    31     }
    32   }
    33 }
    34 impl Objective for City {}
    35 
    36 /// Geo-coordinate Point object type
    37 #[derive(Serialize, Deserialize, Debug, Default, PartialEq)]
    38 pub struct Point {
    39   pub lat: f32,
    40   pub lng: f32,
    41 }
    42 
    43 impl Point {
    44   /// Create a new Point from (f32, f32)
    45   pub fn new(lat: f32, lng: f32) -> Self {
    46     Point { lat, lng }
    47   }
    48 
    49   /// Given an additional Point, and assuming Points are on Earth,
    50   /// returns the distance in kilometers between them using the
    51   /// Haversine formula
    52   pub fn earth_distance_from(&self, other: Point) -> f32 {
    53     let earth_radius_kilometer = 6371.0_f32;
    54     let lat_rads = self.lat.to_radians();
    55     let other_lat_rads = other.lat.to_radians();
    56 
    57     let delta_latitude = (self.lat - other.lat).to_radians();
    58     let delta_longitude = (self.lng - other.lng).to_radians();
    59 
    60     let central_angle_inner = (delta_latitude / 2.0).sin().powi(2)
    61       + lat_rads.cos()
    62         * other_lat_rads.cos()
    63         * (delta_longitude / 2.0).sin().powi(2);
    64     let central_angle = 2.0 * central_angle_inner.sqrt().asin();
    65 
    66     let distance = earth_radius_kilometer * central_angle;
    67 
    68     println!(
    69       "Distance between points on the surface of Earth is {:.1} kilometers",
    70       distance
    71     );
    72 
    73     distance
    74   }
    75 }
    76 
    77 #[test]
    78 fn london_to_paris() {
    79   assert_eq!(
    80     Point::new(48.85341_f32, -2.34880_f32)
    81       .earth_distance_from(Point::new(51.50853_f32, -0.12574_f32)),
    82     334.9559_f32,
    83   );
    84 }
    85 
    86 impl From<City> for Point {
    87   fn from(city: City) -> Self {
    88     city.point
    89   }
    90 }
    91 
    92 impl Objective for Point {}