SlicePolygonIntoEqualParts Method (IGeometryEngine)

In This Topic

Slices a polygon into a set of equal area parts.

Syntax

C#
Visual Basic (Declaration)

IReadOnlyList<Polygon> SlicePolygonIntoEqualParts( 
   Polygon polygon,
   int numParts,
   double angle,
   SliceType sliceType
)

Function SlicePolygonIntoEqualParts( _
   ByVal polygon As Polygon, _
   ByVal numParts As Integer, _
   ByVal angle As Double, _
   ByVal sliceType As SliceType _
) As IReadOnlyList(Of Polygon)

Parameters

polygon: The polygon to slice.
numParts: The number of equal area parts to slice the polygon into. Must be greater than 1.
angle: Angle (in radians) to rotate the polygon before it is sliced. The angle is measured from the positive X-axis in a counterclockwise direction.
sliceType: Controls how the polygon is sliced; into strips or blocks.

Return Value

Returns the polygons. If none are created, then the collection returned is empty.

Exceptions

Exception	Description
System.ArgumentNullException	The polygon is null.
System.ArgumentException	The polygon must be sliced into at least 2 parts.

Remarks

Slicing into strips produces parallel equal area parts. The slicing starts from the bottom of the polygon and proceeds to the top.

The following image illustrates a polygon divided into strips. Each polygon is sliced with a different angle; starting at 0 and increasing by 30 degrees.

PolygonSliceStrips

Slicing into blocks produces equal area parts, not necessarily strips. The slicing is done recursively, each time slicing the polygon into two parts along the larger dimension (height or width).

The following image illustrates a polygon divided into blocks. Each polygon is sliced with a different angle; starting at 0 and increasing by 30 degrees.

PolygonSliceBlocks

Example

Slice a Polygon into equal parts

      
var slices = GeometryEngine.Instance.SlicePolygonIntoEqualParts(polygon, 3, 0, SliceType.Blocks);
// slices.Count = 3


// simple polygon
List<Coordinate2D> list2D = new List<Coordinate2D>();
list2D.Add(new Coordinate2D(1.0, 1.0));
list2D.Add(new Coordinate2D(1.0, 2.0));
list2D.Add(new Coordinate2D(2.0, 2.0));
list2D.Add(new Coordinate2D(2.0, 1.0));

Polygon p = PolygonBuilderEx.CreatePolygon(list2D);
slices = GeometryEngine.Instance.SlicePolygonIntoEqualParts(p, 2, 0, SliceType.Strips);

// slice[0] coordinates - (1.0, 1.0), (1.0, 1.5), (2.0, 1.5), (2.0, 1.0), (1.0, 1.0) 
// slice[1] coordinates - (1.0, 1.5), (1.0, 2.0), (2.0, 2.0), (2.0, 1.5), (1.0, 1.5)

slices = GeometryEngine.Instance.SlicePolygonIntoEqualParts(p, 2, Math.PI / 4, SliceType.Strips);

// slice[0] coordinates - (1.0, 1.0), (1.0, 2.0), (2.0, 1.0), (1.0, 1.0)
// slice[1] coordinates - (1.0, 2.0), (2.0, 2.0), (2.0, 1.0), (1.0, 2.0)

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

IGeometryEngine Interface
IGeometryEngine Members

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