elevation

Get elevations from coordinates and names of locations.

Get an elevation from coordinates: ```rust let e = Elevation::from_coords(45.0, 100.0).await.unwrap();

println!("({}, {}): {}", e.latitude, e.longitude, e.elevation); (45, 100): 2057 ```

Get elevations from multiple coordinates: ```rust let e = Elevation::frommultiplecoords(vec![[40.828, -73.9206], [41.1955, -82.424]]) .await .unwrap();

for x in e {
    println!("({}, {}): {}", x.latitude, x.longitude, x.elevation);
}

(40.828, -73.9206): 12 (41.1955, -82.424): 277 ```

Get an elevation from the name of a location: ```rust let e = Elevation::from_location("Seattle, Washington") .await .unwrap();

println!("({}, {}): {}", e.latitude, e.longitude, e.elevation); (47.6038321, -122.3300624): 77.5 ```