osm_graph 0.1.2

This library provides a set of tools for generating isochrones from geographic coordinates. It leverages OpenStreetMap data to construct road networks and calculate areas accessible within specified time limits. The library is designed for both Rust and Python, offering high performance and easy integration into data science workflows.
Documentation 
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use geo::Polygon;
use geojson::{GeoJson, Geometry, Value};

pub fn calculate_distance(lat1: f64, lon1: f64, lat2: f64, lon2: f64) -> f64 {
    let radius_earth = 6371000.0; // Radius of the Earth in meters

    let dlat = (lat2 - lat1).to_radians();
    let dlon = (lon2 - lon1).to_radians();

    let lat1 = lat1.to_radians();
    let lat2 = lat2.to_radians();

    let a = (dlat / 2.0).sin().powi(2) + (dlon / 2.0).sin().powi(2) * lat1.cos() * lat2.cos();
    let c = 2.0 * a.sqrt().asin();

    radius_earth * c // Distance in meters
}

pub fn calculate_travel_time(length: f64, speed_kph: f64) -> f64 {
    let speed_m_per_s = speed_kph / 3.6;
    length / speed_m_per_s // Returns time in seconds
}

pub fn polygon_to_geojson(polygon: &Polygon<f64>) -> GeoJson {
    // node_to_latlon returns (lat, lon) tuples which geo stores as (x=lat, y=lon).
    // GeoJSON spec requires [longitude, latitude], so coord.y = lon, coord.x = lat.
    let exterior_coords = polygon
        .exterior()
        .0
        .iter()
        .map(|coord| vec![coord.y, coord.x]) // [lon, lat] per GeoJSON spec
        .collect::<Vec<_>>();

    let geojson_polygon = Geometry::new(Value::Polygon(vec![exterior_coords]));

    GeoJson::Geometry(geojson_polygon)
}

// Convert polygon to GeoJSON string
pub fn polygon_to_geojson_string(polygon: &Polygon<f64>) -> String {
    let geojson = polygon_to_geojson(polygon);
    geojson.to_string()
}