Represents a shape defined by one or more rings, where each ring is a set of points with the same start and end point.

Namespace:  ESRI.ArcGISExplorer.Geometry

Assembly:  ESRI.ArcGISExplorer (in ESRI.ArcGISExplorer.dll) Version: 2.0.0.1500 (2.0.0.1500)

Syntax

C#
public sealed class Polygon : Geometry, 
	IXmlSerializable
Visual Basic (Declaration)
Public NotInheritable Class Polygon _
	Inherits Geometry _
	Implements IXmlSerializable

Remarks

Polygon geometries represent area shapes, and can be used to represent geographical features such as countries, lakes, or land parcels. Polygons may be found as the Geometry in a spatially-enabled Table, or as the Geometry of a Graphic.

A Polygon geometry comprises multiple Point objects; Point objects are used to build up or change a Polygon geometry (for example by using the AddPoint, InsertPoint, RemovePointAt, or SetPoint methods), or to retrieve information about the Polygon (GetPoint). See the example code below for an example of creating a new Polygon and defining its vertices using the AddPoint method.

Polygons may be made up of multiple sections called rings which define holes or multiple different areas of the polygon shape. A Polygon with multiple paths is known as a multipart shape. Overloaded methods are available to work specifically with multipart polygons (for example AddPoint(Int32, Point), InsertPoint(Int32, Int32, Point), RemovePointAt(Int32, Int32), SetPoint(Int32, Int32, Point), and GetPoint(Int32, Int32)). The points of a Polygon are retrieved and set by value; therefore new points are always copied in to the Polygon, not added directly.

If building up a by specifying individual vertices, bear in mind the following:

  • The last vertex in every ring of a Polygon should be the same as the first vertex in the same ring; this ensures that every ring is a closed shape. Use the Close()()() method to ensure each ring of a Polygon is closed.
  • Each ring in a Polygon should not self-intersect; if a ring self-intersects it can be defined instead as two separate rings.
  • The vertices in each ring which defines an outer boundary of Polygon should traverse the ring in a clockwise direction. If the ring defines an inner boundary of the Polygon (a hole), the vertices should traverse the ring in a counter-clockwise direction.

These rules of geometrical correctness can be applied by using the GeometryOperations.Simplify method.

Examples

The code below demonstrates the creation of a simple Polygon using the AddPoint and Close methods. The individual points in the Polygon are also retrieved using the GetPoint method and this information is used to add a Note with popup information to the current map in the application.
CopyC#
// Create a new Polygon, allowing the default CoordinateSystem of WGS84.
Polygon poly = new Polygon();

// Add a series of points to the Polygon (overloads are available to add multiple Points.
poly.AddPoint(new ESRI.ArcGISExplorer.Geometry.Point(2.33434596343321, 48.8628885302916));
poly.AddPoint(new ESRI.ArcGISExplorer.Geometry.Point(2.33269733037166, 48.8603451299656));
poly.AddPoint(new ESRI.ArcGISExplorer.Geometry.Point(2.33659764618658, 48.8594678571346));
poly.AddPoint(new ESRI.ArcGISExplorer.Geometry.Point(2.33960511237599, 48.8591968205275));
poly.AddPoint(new ESRI.ArcGISExplorer.Geometry.Point(2.340578062027, 48.8608773611669));
// Ensure the Polygon is a closed shape.
poly.Close();

// Create a Note using the polygon shape.
Note louvre = new Note("The Louvre", poly, Symbol.Fill.SolidOutline.Green);

// Populate the Note popup information using information about the Polygon.
StringBuilder info = new StringBuilder(@"<p><a href=""http://www.louvre.fr"">The Louvre, Paris</a></p>");
for (int i = 0; i < poly.PointCount(); i++)
{
    ESRI.ArcGISExplorer.Geometry.Point pt = poly.GetPoint(i);
    info.AppendLine(@"<p>" + i.ToString() + ": " + pt.ToString() + @"</p>");
}

MapDisplay disp = ESRI.ArcGISExplorer.Application.Application.ActiveMapDisplay;
louvre.Popup.Content = info.ToString();

// Add the Note to the current Map.
disp.Map.ChildItems.Add(louvre);
CopyVB.NET
' Create a new Polygon, allowing the default CoordinateSystem of WGS84.
Dim poly As Polygon = New Polygon()

' Add a series of points to the Polygon (overloads are available to add multiple Points.
poly.AddPoint(New ESRI.ArcGISExplorer.Geometry.Point(2.33434596343321, 48.8628885302916))
poly.AddPoint(New ESRI.ArcGISExplorer.Geometry.Point(2.33269733037166, 48.8603451299656))
poly.AddPoint(New ESRI.ArcGISExplorer.Geometry.Point(2.33659764618658, 48.8594678571346))
poly.AddPoint(New ESRI.ArcGISExplorer.Geometry.Point(2.33960511237599, 48.8591968205275))
poly.AddPoint(New ESRI.ArcGISExplorer.Geometry.Point(2.340578062027, 48.8608773611669))
' Ensure the Polygon is a closed shape.
poly.Close()

' Create a Note using the polygon shape.
Dim louvre As Note = New Note("The Louvre", poly, Symbol.Fill.SolidOutline.Green)

' Populate the Note popup information using information about the Polygon.
Dim info As StringBuilder = New StringBuilder("<p><a href=""http://www.louvre.fr"">The Louvre, Paris</a></p>")
For i As Integer = 0 To poly.PointCount() - 1
    Dim pt As ESRI.ArcGISExplorer.Geometry.Point = poly.GetPoint(i)
    info.AppendLine("<p>" & i.ToString() & ": " & pt.ToString() & "</p>")
Next

Dim disp As MapDisplay = ESRI.ArcGISExplorer.Application.Application.ActiveMapDisplay
louvre.Popup.Content = info.ToString()

' Add the Note to the current Map.
disp.Map.ChildItems.Add(louvre)

Inheritance Hierarchy

System..::.Object

  ESRI.ArcGISExplorer.Geometry..::.Geometry

    ESRI.ArcGISExplorer.Geometry..::.Polygon

See Also