Provides access to members that construct an angle using other geometries and measures. This interface is implemented by the GeometryEnvironment object.
Description
ConstructAngle returns the angle formed either by three input points used to define the angle or an input line (and the implied baseline). The constructed angle is returned in radians and is always between -Pi and Pi.
Members
| Name | Description | |
|---|---|---|
|  | ConstructLine | Constructs the angle between the infinite line containing the input line segment and the positive x-axis. | 
|  | ConstructThreePoint | Constructs the angle included in three points. | 
IConstructAngle.ConstructLine Method
Constructs the angle between the infinite line containing the input line segment and the positive x-axis.
Public Function ConstructLine ( _
    ByVal inLine As ILine _
) As Double
public double ConstructLine (
    ILine inLine
);
Description
ConstructLine returns the Angle defined by a given Line input. This is the same Angle returned by the ILine::Angle method. The Angle is displacement of the Line from a baseline through the From Point extending in the positive X direction. The returned angle is the smaller angle with measure between -Pi and Pi.
Remarks

Private Shared Sub constructLine()
     Dim pPtFrom As IPoint
     Dim pPtTo As IPoint
     pPtFrom = New Point
     pPtTo = New Point
     Dim pLine As ILine
     pLine = New Line
     pPtFrom.PutCoords(0, 0)
     pPtTo.PutCoords(1, 1)
     pLine.PutCoords(pPtFrom, pPtTo)
     Dim pCAngle As IConstructAngle
     Dim pGEnv As GeometryEnvironment
     pGEnv = New GeometryEnvironment
     pCAngle = pGEnv
     Dim dAngle As Double
     dAngle = pCAngle.ConstructLine(pLine)
     MsgBox("The angle from the x-axis to the line is " & dAngle)
End Sub
IConstructAngle.ConstructThreePoint Method
Constructs the angle included in three points.
Public Function ConstructThreePoint ( _
    ByVal from As IPoint, _
    ByVal through As IPoint, _
    ByVal to As IPoint _
) As Double
public double ConstructThreePoint (
    IPoint from,
    IPoint through,
    IPoint to
);
Description
ConstructThreePoint returns the Angle formed by three input points. The returned angle is the smaller angle formed by an imaginary line from the first to the second point and the second to the third point. The measure of the constructed angle is between -Pi and Pi. The returned angle can also be thought of as the displacement angle of a line from the second point to the third point with a baseline formed by the first point and second point.
Remarks

// Calculates the angle defined by the 3 points.
public void constructAngle()
{
    IPoint fromPoint = new ESRI.ArcGIS.Geometry.Point();
    IPoint throughPoint = new ESRI.ArcGIS.Geometry.Point();
    IPoint toPoint = new ESRI.ArcGIS.Geometry.Point();
    fromPoint.PutCoords(1, 0);
    toPoint.PutCoords(1, 1);
    throughPoint.PutCoords(0, 0);
    GeometryEnvironment geometryEnvironment = new GeometryEnvironment();
    IConstructAngle constructAngle = geometryEnvironment as IConstructAngle;
    double angle = constructAngle.ConstructThreePoint(fromPoint, throughPoint, toPoint);
    System.Windows.Forms.MessageBox.Show("The constructed angle is " + angle);
}
' Calculates the angle defined by the 3 points.
    Public Sub t_construct_angle()
        Dim pPtFrom As IPoint
        Dim pPtThrough As IPoint
        Dim pPtTo As IPoint
        pPtFrom = New Point
        pPtThrough = New Point
        pPtTo = New Point
        pPtFrom.PutCoords(1, 0)
        pPtTo.PutCoords(1, 1)
        pPtThrough.PutCoords(0, 0)
        Dim pCAngle As IConstructAngle
        Dim pGEnv As GeometryEnvironment
        pGEnv = New GeometryEnvironment
        pCAngle = pGEnv
        Dim dAngle As Double
        dAngle = pCAngle.ConstructThreePoint(pPtFrom, pPtThrough, pPtTo)
        MsgBox("The constructed angle is " & dAngle)
    End Sub
Classes that implement IConstructAngle
| Classes | Description | 
|---|---|
| GeometryEnvironment | Provides a way of creating geometries from different inputs and setting/getting global variables for controlling behavior of geometry methods. |