public static decimal GetArea(FeatureCollection feats)
{
var features = feats.Clone();
var coordinate = features.Features.FirstOrDefault().Geometry.Coordinates.FirstOrDefault();
var zone = 1 + (int)Math.Floor((coordinate.X + 180) / 6);
var zoneIsNorth = (coordinate.Y * Math.PI / 180) < 0 ? false : true;
features = TransformProjection(features, GeographicCoordinateSystem.WGS84, ProjectedCoordinateSystem.WGS84_UTM(zone, zoneIsNorth));
decimal area = 0;
foreach (var feature in features.Features)
{
for (var i = 0; i < feature.Geometry.NumGeometries; i++)
{
area += (decimal)feature.Geometry.GetGeometryN(i).Area;
}
}
return(area);
}