/// <summary>
/// Computes the geometric union of a <see cref="IList{IGeometry}"/><para/>
/// If no input geometries were provided but a <see cref="IGeometryFactory"/> was provided,
/// an empty <see cref="IGeometryCollection"/> is returned.
/// </summary>
/// <param name="geoms">A collection of geometries</param>
/// <param name="geomFact">The geometry factory to use if the collection is empty</param>
/// <returns>The union of the geometries
/// or an empty GEOMETRYCOLLECTION</returns>
public static IGeometry Union(IList <IGeometry> geoms, IGeometryFactory geomFact)
{
var op = new UnaryUnionOp(geoms, geomFact);
return(op.Union());
}
/// <summary>Constructs a unary union operation for a <see cref="IGeometry"/>
/// (which may be a <see cref="IGeometryCollection"/>).
/// </summary>
/// <param name="geom">A geometry to union</param>
/// <returns>The union of the elements of the geometry
/// or an empty GEOMETRYCOLLECTION</returns>
public static IGeometry Union(IGeometry geom)
{
var op = new UnaryUnionOp(geom);
return(op.Union());
}
/// <summary>
/// Computes the geometric union of a <see cref="IList{IGeometry}"/>
/// </summary>
/// <param name="geoms">A collection of geometries</param>
/// <returns>The union of the geometries,
/// or <c>null</c> if the input is empty</returns>
public static IGeometry Union(IList <IGeometry> geoms)
{
var op = new UnaryUnionOp(geoms);
return(op.Union());
}