ArcGIS Developer Help

IArea Interface

Provides access to members that return properties common to rings and polygons.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Description

Use the IArea interface to get the Area of a Geometry. It can also be used to get the Centroid point and Label point for a Geometry.

Members

	Name	Description
	Area	The area.
	Centroid	The center of gravity (centroid).
	LabelPoint	A point guaranteed to be inside this area.
	QueryCentroid	Copies the centroid of this area to the specified point.
	QueryLabelPoint	Copies to the input point a point guaranteed to be inside this area.

Classes that implement IArea

Classes	Description
Envelope	A rectangle with sides parallel to a coordinate system defining the extent of another geometry; optionally has min and max measure, height and ID attributes.
MultiPatch	A collection of surface patches.
Polygon	A collection of rings ordered by their containment relationship; optionally has measure, height and ID attributes.
Ring	An area bounded by one, closed sequence of connected segments; optionally has measure, height and ID attributes at each vertex.

[C#]

[C#]

// The example shows how to get the properties for a selected polygon in
// an ArcMap edit session.
public void showPolygonProperties()
{
    //get editor extension
    UID editorUID = new UIDClass();
    editorUID.Value = "esriEditor.Editor";
    IEditor editor = m_application.FindExtensionByCLSID(editorUID) as IEditor;
    if (editor.SelectionCount != 1)
    {
        System.Windows.Forms.MessageBox.Show("Start Editor and select one polygon");
        return;
    }
    IEnumFeature selectedFeatures = editor.EditSelection;
    IPoint centerPoint = new ESRI.ArcGIS.Geometry.Point();
    IPoint labelPoint = new ESRI.ArcGIS.Geometry.Point();
    IFeature feature = selectedFeatures.Next();
    while (feature != null)
    {
        if (feature.Shape.GeometryType == esriGeometryType.esriGeometryPolygon)
        {
            IArea area = feature.Shape as IArea;
            String message = "+++Polygon.IArea properties...\n" +
            "Area = " + area.Area + "\n" +
            "Center.X = " + area.Centroid.X + "\n" +
            "Center.Y = " + area.Centroid.Y + "\n" +
            "LabelPoint.X = " + area.LabelPoint.X + "\n" +
            "LabelPoint.Y = " + area.LabelPoint.Y;
            area.QueryCentroid(centerPoint);
            area.QueryLabelPoint(labelPoint);
            message = message + "\n" + "+++Polygon.IArea Queries..." + "\n" +
            "Center = " + centerPoint.X + "," + centerPoint.Y + "\n" +
            "Label = " + labelPoint.X + "," + labelPoint.Y;
            System.Windows.Forms.MessageBox.Show(message);
        }
        feature = selectedFeatures.Next();
    }
}

[Visual Basic .NET]

' The example shows how to get the properties for a selected polygon in ' an ArcMap edit session. Public Sub t_IArea_polygon() Dim pID As New UID pID = "esriEditor.editor" Dim pEditor As IEditor Dim pApp As IApplication Set pApp = Application Set pEditor = pApp.FindExtensionByCLSID(pID) If pEditor.SelectionCount <> 1 Then MsgBox "select one polygon" Exit Sub End If Dim pEnumFeat As IEnumFeature Dim pFeature As IFeature Dim i As Long Set pEnumFeat = pEditor.EditSelection Dim pArea As IArea Dim pCenter As IPoint Dim pLabel As IPoint Set pCenter = New Point Set pLabel = New Point Set pFeature = pEnumFeat.Next While Not pFeature Is Nothing If pFeature.Shape.GeometryType = esriGeometryPolygon Then Set pArea = pFeature.Shape MsgBox "+++Polygon::IArea properties..." & vbCrLf _ & "Area = " & pArea.Area & vbCrLf _ & "Center.X = " & pArea.Centroid.X & vbCrLf _ & "Center.Y = " & pArea.Centroid.Y & vbCrLf _ & pArea.LabelPoint.X & vbCrLf _ & "LabelPoint.Y = " & pArea.LabelPoint.Y pArea.QueryCentroid pCenter pArea.QueryLabelPoint pLabel MsgBox "+++Polygon::IArea Queries..." & vbCrLf _ & "Center = " & pCenter.X & "," & pCenter.Y & vbCrLf _ & "Label = " & pLabel.X & "," & pLabel.Y & vbCrLf End If Set pFeature = pEnumFeat.Next Wend End Sub

`.NET Samples`

Move a graphic along a path in ArcMap Custom map selection commands Tabbed feature inspector Calculate area geoprocessing function tool 3D multipatch examples Custom subtyped command and tool Tabbed feature inspector