MgMultiPolygon Class Reference

An MgMultiPolygon is a two-dimensional aggregate geometry whose elements are MgPolygon geometries. More...

Inheritance diagram for MgMultiPolygon:

List of all members.

Public Member Functions
virtual MgGeometricEntity *	Copy ()
virtual MgCoordinateIterator *	GetCoordinates ()
	Returns an iterator over the coordinates included in this geometric entity.
virtual INT32	GetCount ()
virtual INT32	GetDimension ()
virtual INT32	GetGeometryType ()
virtual MgPolygon *	GetPolygon (INT32 index)
virtual bool	IsClosed ()
virtual bool	IsEmpty ()
virtual MgGeometricEntity *	Transform (MgTransform *transform)
	Returns a transformed copy of this geometric entity.

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Detailed Description

An MgMultiPolygon is a two-dimensional aggregate geometry whose elements are MgPolygon geometries.

Remarks:

The polygons are not connected or ordered. An instance of this class is constructed by calling a non-static MgGeometryFactory::CreateMultiPolygon() method and, once constructed, is immutable.

Example (PHP)
The following code shows the construction of an MgMultiPolygon geometry. Review the MgPolygon example code.

 // A helper class additional to those created in the
 // MgPolygon example code is needed.
 $polygonCollection = new MgPolygonCollection();
 // After each MgPolygon geometry is constructed,
 // it is added to an MgPolygonCollection.
 $index = $polygonCollection->Add($polygon);
 echo "A polygon is added to a polygon collection at index: $index\n";

 // construct the MgMultiPolygon geometry
 $multiPolygon = $geometryFactory->
 CreateMultiPolygon($polygonCollection);

 // print out the Agf Text string for the geometry
 $multiPolygonAgfText =
 $wktReaderWriter->Write($multiPolygon);
 echo "AGF Text representation of MultiPolygon: $multiPolygonAgfText\n";

Example (C#)
The CreateAMultiPolygonXY method calls the CreateAPolygonXY method. The code for the CreateAPolygonXY method is in the MgPolygon example code.

 using OSGeo.MapGuide;

 private MgWktReaderWriter wktReaderWriter;
 private MgGeometryFactory geometryFactory;
 private MgMultiPolygon mpnPn0010110100Pn0010110100;
 // this array contains the data for 2 polygons whose values are identical
 private double[][][,] mpnPn0010110100Pn0010110100Data;
 // the following array is used for the exterior ring of a polygon
 // the points are in counterclockwise order
 private double[,] da0010110100 = { { 0, 0 }, { 1, 0 }, { 1, 1 }, { 0, 1 }, { 0, 0 } };
 private String geometryAgfText;

 public MgMultiPolygon CreateAMultiPolygonXY(double[][][,] polygonData)
 {
     MgPolygonCollection polygons = new MgPolygonCollection(); ;
     for (int i = 0; i < polygonData.GetLength(0); i++)
     {
         polygons.Add(CreateAPolygonXY(polygonData[i]));
     }
     return geometryFactory.CreateMultiPolygon(polygons);
 }

 geometryFactory = new MgGeometryFactory();
 pnEr0010110100Data = new double[1][,];
 pnEr0010110100Data[0] = da0010110100;
 mpnPn0010110100Pn0010110100Data = new double[2][][,];
 mpnPn0010110100Pn0010110100Data[0] = pnEr0010110100Data;
 mpnPn0010110100Pn0010110100Data[1] = pnEr0010110100Data;
 mpnPn0010110100Pn0010110100 = CreateAMultiPolygonXY(mpnPn0010110100Pn0010110100Data);

 // print out the Agf Text string for the geometry
 wktReaderWriter = new MgWktReaderWriter();
 geometryAgfText = wktReaderWriter.Write(mpnPn0010110100Pn0010110100);
 // geometryAgfText now contains:
 // "MULTIPOLYGON XY ((( 0 0, 1 0, 1 1, 0 1, 0 0 )), (( 0 0, 1 0, 1 1, 0 1, 0 0 )))"