ArcObjects Library Reference (Geometry)

ICircularArc Interface

Provides access to members that control properties of circular arcs.

Product Availability

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

Description

A CircularArc is an object that describes any portion of a circle. The size of the CircularArc is determined by the length of the Radius and the Central Angle. CircularArcs can be constructed by numerous different methods given a wide variety of input parameters. A CircularArc differs from an EllipticArc in that every point along the CircularArc must be a fixed distance (the Radius) from the CenterPoint.

Members

		Description
	CenterPoint	The center point.
	CentralAngle	The included (or central) angle.
	ChordHeight	The chord height (assigning preserves endpoints, and orientation unless chord height is < 0).
	Complement	Changes this arc into its complement; 'from' and 'to' points are unchanged.
	Dimension	The topological dimension of this geometry.
	Envelope	Creates a copy of this geometry's envelope and returns it.
	FromAngle	The angle, measured from a horizontal line through this circular arc's center point, that defines where this arc starts.
	FromPoint	The 'from' point of the curve.
	GeometryType	The type of this geometry.
	GeoNormalize	Shifts longitudes, if need be, into a continuous range of 360 degrees.
	GeoNormalizeFromLongitude	Normalizes longitudes into a continuous range containing the longitude. This method is obsolete.
	GetSubcurve	Extracts a portion of this curve into a new curve.
	IsClosed	Indicates if 'from' and 'to' points (of each part) are identical.
	IsCounterClockwise	Indicates if this circular is oriented counter-clockwise from its 'from' point to its 'to' point.
	IsEmpty	Indicates whether this geometry contains any points.
	IsLine	Indicates if the arc has degenerated to a line (radius is infinite).
	IsMinor	Indicates whether this circular arc is a minor arc or a major arc.
	IsPoint	Indicates if the arc has degenerated to a point (radius is 0).
	Length	The length of the curve.
	Project	Projects this geometry into a new spatial reference.
	PutCoords	Defines this arc by a center point, 'from' and 'to' points, and orientation. If the from and to points do not lie on the same circle, the arc's center point will be adjusted.
	PutCoordsByAngle	Defines this circular arc by a center point, 'from' angle, signed central angle, and radius.
	PutRadiusByPoint	Defines the radius of this circular arc to be the distance from the arc's center point to the input point; other properties remain unchanged.
	QueryCenterPoint	Copies the center point of this circular arc to the input point.
	QueryCoords	Copies the center, 'from' and 'to' points, orientation and major/minor property into the input parameters.
	QueryCoordsByAngle	Returns the center point, 'from' angle, signed central angle, and radius.
	QueryEnvelope	Copies this geometry's envelope properties into the specified envelope.
	QueryFromPoint	Copies this curve's 'from' point to the input point.
	QueryNormal	Constructs a line normal to a curve from a point at a specified distance along the curve.
	QueryPoint	Copies to outPoint the properties of a point on the curve at a specified distance from the beginning of the curve.
	QueryPointAndDistance	Finds the point on the curve closest to inPoint, then copies that point to outPoint; optionally calculates related items.
	QueryTangent	Constructs a line tangent to a curve from a point at a specified distance along the curve.
	QueryToPoint	Copies the curve's 'to' point into the input point.
	Radius	The radius.
	ReverseOrientation	Reverses the parameterization of the curve ('from' point becomes 'to' point, first segment becomes last segment, etc).
	SetEmpty	Removes all points from this geometry.
	SnapToSpatialReference	Moves points of this geometry so that they can be represented in the precision of the geometry's associated spatial reference system.
	SpatialReference	The spatial reference associated with this geometry.
	ToAngle	The angle, measured from a horizontal line through this circular arc's center point, that defines where this arc ends.
	ToPoint	The 'to' point of the curve.

Inherited Interfaces

Interfaces	Description
ICurve	Provides access to properties and methods of all 1 dimensional curves (polylines, segments, boundaries of polygons, etc.).
IGeometry	Provides access to members that describe properties and behavior of all geometric objects.

CoClasses that implement ICircularArc

CoClasses and Classes	Description
CircularArc	A portion of a circle that connects two points optionally has measure, height and ID attributes at each endpoint.

Remarks

ICircularArc Example

[C#]

    private void OutputArcProperties(ICircularArc circularArc)
    {
        String report = "Center Point: (" + circularArc.CenterPoint.X + ", " +
              circularArc.CenterPoint.Y + ")" + "\n" +
        "From Point: (" + circularArc.FromPoint.X + ", " +
              circularArc.FromPoint.Y + ")" + "\n" +
        "To Point: (" + circularArc.ToPoint.X + ", " +
              circularArc.ToPoint.Y + ")" + "\n" +
        "From Angle: " + circularArc.FromAngle + "\n" +
        "Central Angle: " + circularArc.CentralAngle + "\n" +
        "To Angle: " + circularArc.ToAngle + "\n" +
        "Radius: " + circularArc.Radius + "\n" +
        "Chord Height: " + circularArc.ChordHeight + "\n" +
        "IsCounterClockwise: " + circularArc.IsCounterClockwise + "\n" +
        "IsMinor: " + circularArc.IsMinor + "\n" +
        "IsLine: " + circularArc.IsLine + "\n" +
        "IsPoint: " + circularArc.IsPoint + ")";
        //IsLine and IsPoint check for degenerate cases of CircularArcs
        System.Windows.Forms.MessageBox.Show(report);
    }