pub const EARTH_RADIUS_MILES: f64 = 3958.8;

pub fn latlong_to_xy(lat: f64, long: f64) -> (f64, f64) {
    // x = r λ cos(φ0)
    // y = r φ
    (EARTH_RADIUS_MILES * long * lat.cos(), EARTH_RADIUS_MILES * lat)
}