project method
Implementation
@override
CustomPoint project(LatLng latlng) {
var d = math.pi / 180;
var max = maxLatitude;
var lat = math.max(math.min(max, latlng.latitude), -max);
var sin = math.sin(lat * d);
return CustomPoint(
r * latlng.longitude * d, r * math.log((1 + sin) / (1 - sin)) / 2);
}