use time::{Date, Month}; use wmm::declination; fn main() { let date = Date::from_calendar_date(2021, Month::September, 1).unwrap(); let lat = 29.7363025; let lon = -93.8827939; let dec = declination(date, lat, lon).unwrap(); println!( "Today's declination for coordinates {},{} is {}°", lat, lon, dec ) }