ArcObjects Library Reference (Geometry)  

IEllipticArc Interface

Provides access to members that control properties of elliptic arc segments.

Product Availability

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

Description

An Elliptic Arc is an object that describes any portion of an ellipse.  The Major axis of the Elliptic Arc is the largest axis spanning between points on opposite sides of the ellipse.  The Minor axis is the perpendicular bisector of the Major axis.  Together, the Major and Minor axes determine the full ellipse on which the Elliptic Arc is generated.  These parameters may also be specified in terms of the semi-Major axis (half of the Major axis) and the MinorMajorRatio (the ratio of the Minor axis to the Major axis).  The ellipse may also be rotated.  Rotation is described by the Rotation Angle.  However, the effect of the Rotation Angle depends on the value of EllipseStd.  If EllipseStd is TRUE, all angles and axes are calculated with respect to the Major Axis as though the Major Axis was at 0 radians.  Also, the location of the From Point and To Point are given relative to the Center Point as though it is the origin.  If EllipseStd is FALSE, all angles are caluclated in standard Cartesian coordinates.  The portion of the complete ellipse represented by the Elliptic Arc is determined by the From Angle and Central Angle, both measured in radians.

Members

Description
Read-only property CenterPoint The center point of the arc.
Read/write property CentralAngle The included (or central) angle.
Method Complement Changes this ellipse into its complement; 'from' and 'to' points are unchanged.
Read-only property Dimension The topological dimension of this geometry.
Read-only property Envelope Creates a copy of this geometry's envelope and returns it.
Read/write property FromAngle The start angle (measured from a horizontal line through the center point) defining where the arc starts.
Read/write property FromPoint The 'from' point of the curve.
Read-only property GeometryType The type of this geometry.
Method GeoNormalize Shifts longitudes, if need be, into a continuous range of 360 degrees.
Method GeoNormalizeFromLongitude Normalizes longitudes into a continuous range containing the longitude. This method is obsolete.
Method GetAxes Gets the semi-major and semi-minor axes.
Method GetSubcurve Extracts a portion of this curve into a new curve.
Read-only property IsCircular Indicates if this elliptical arc is acutally circular (major and minor axes same length).
Read-only property IsClosed Indicates if 'from' and 'to' points (of each part) are identical.
Read/write property IsCounterClockwise Indicates if this elliptic arc is oriented counter-clockwise from its 'from' point to its 'to' point.
Read-only property IsEmpty Indicates whether this geometry contains any points.
Read-only property IsLine Indicates if the arc is degenerated to a line.
Read/write property IsMinor Indicates whether the arc is a minor arc or a major arc.
Read-only property IsPoint Indicates if the arc is degenerated to a point.
Read-only property Length The length of the curve.
Method Project Projects this geometry into a new spatial reference.
Method PutAxes Sets the semi-major and semi-minor axes.
Method PutCoords Sets the center point and endpoints, angle of rotation, and orientation.
Method PutCoordsByAngle Sets the center point, starting angle, signed central angle, angle of rotation, ratio of the minor axis to the major axis, and axes.
Method QueryCenterPoint Copies the center of this arc to the input point.
Method QueryCoords Copies the center and endpoints, angle of rotation, orientation and major/minor properties into the method parameters.
Method QueryCoordsByAngle Returns the center point, starting angle, signed central angle, angle of rotation, ratio of the minor axis to the major axis, and axes.
Method QueryEnvelope Copies this geometry's envelope properties into the specified envelope.
Method QueryFromPoint Copies this curve's 'from' point to the input point.
Method QueryNormal Constructs a line normal to a curve from a point at a specified distance along the curve.
Method QueryPoint Copies to outPoint the properties of a point on the curve at a specified distance from the beginning of the curve.
Method QueryPointAndDistance Finds the point on the curve closest to inPoint, then copies that point to outPoint; optionally calculates related items.
Method QueryTangent Constructs a line tangent to a curve from a point at a specified distance along the curve.
Method QueryToPoint Copies the curve's 'to' point into the input point.
Method ReverseOrientation Reverses the parameterization of the curve ('from' point becomes 'to' point, first segment becomes last segment, etc).
Method SetEmpty Removes all points from this geometry.
Method SnapToSpatialReference Moves points of this geometry so that they can be represented in the precision of the geometry's associated spatial reference system.
Read/write property SpatialReference The spatial reference associated with this geometry.
Read/write property ToAngle The end angle (measured from a horizontal line through the center point) defining where the arc ends.
Read/write property 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 IEllipticArc

CoClasses and Classes Description
EllipticArc A portion of the boundary of a 2D ellipse that connects two points; optionally has measure, height and ID attributes at each endpoint.

Remarks

A CircularArc is a special case of an EllipticArc where the MinorMajorRatio is 1 (however, a CircularArc is NOT an EllipticArc).

EllipticArc Example

See Also

IPoint Interface | IEnvelope Interface | IGeometry Interface | ISegment Interface | IConstructEllipticArc Interface

.NET Related Topics

How to use the IEnumSegment methods | How to use the IEnumVertex methods | How to work with IEllipticArc properties |