Constructing and reading

var oslo   = new GeoCoordinate(59.9139, 10.7522);
var bergen = new GeoCoordinate(60.3913, 5.3221);

double lat = oslo.Latitude;      // 59.9139…  (NaN when empty)
double lon = oslo.Longitude;     // 10.7522…  (NaN when empty)

Console.WriteLine(oslo);         // "59.9139, 10.7522"
GeoCoordinate.TryParse("59.9139, 10.7522", out var parsed);