ArcObjects Library Reference  (Geometry)    

ITopologicalOperator Interface

Provides access to members for constructing new geometries based upon topological relationships between existing geometries.

Product Availability

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

Members

Description
Read-only property Boundary The boundary of this geometry. A polygon's boundary is a polyline. A polyline's boundary is a multipoint. A point or multipoint's boundary is an empty point or multipoint.
Method Buffer Constructs a polygon that is the locus of points at a distance less than or equal to a specified distance from this geometry.
Method Clip Constructs the intersection of this geometry and the specified envelope.
Method ClipDense Constructs the intersection of this geometry and the specified envelope; densifies lines in output contributed by the clipping envelope.
Method ConstructUnion Defines this geometry to be the union of the inputs. More efficient for unioning multiple geometries than calling Union repeatedly.
Method ConvexHull Constructs the convex hull of this geometry.
Method Cut Splits this geometry into a part left of the cutting polyline, and a part right of it.
Method Difference Constructs the geometry containing points from this geometry but not the other geometry.
Method Intersect Constructs the geometry that is the set-theoretic intersection of the input geometries. Use different resultDimension values to generate results of different dimensions.
Read-only property IsKnownSimple Indicates whether this geometry is known (or assumed) to be topologically correct.
Read-only property IsSimple Indicates whether this geometry is known (or assumed) to be topologically correct, after explicitly determining this if the geometry is not already known (or assumed) to be simple.
Method QueryClipped Redefines clippedGeometry to be the intersection of this geometry and the clipping envelope.
Method QueryClippedDense Redefines clippedGeometry to be the intersection of this geometry and the clipping envelope; densifies lines in the output contributed by the clipping envelope.
Method Simplify Makes this geometry topologically correct.
Method SymmetricDifference Constructs the geometry that contains points from either but not both input geometries.
Method Union Constructs the geometry that is the set-theoretic union of the input geometries.

CoClasses that implement ITopologicalOperator

CoClasses and Classes Description
GeoEllipse (esriMilitaryAnalyst) A spheroidal ellipse.
GeometryBag An ordered collection of objects that support the IGeometry interface.
GeoPolygon (esriMilitaryAnalyst) A spheroidal polygon.
GeoPolyline (esriMilitaryAnalyst) A spheroidal polyline.
MultiPatch A collection of surface patches.
Multipoint An ordered collection of points; optionally has measure, height and ID attributes.
Point An two dimensional point, optionally with measure, height, and ID attributes.
Polygon A collection of rings ordered by their containment relationship; optionally has measure, height and ID attributes.
Polyline An ordered collection of paths; optionally has measure, height and ID attributes.

Remarks

The Buffer, Clip, and Simplify methods only are supported on GeometryBags.

ITopologicalOperator methods must be applied on high-level geometries only. High-Level geometries are point, multipoint, polyline and polygon. To use this method with low-level geometries such as segments (Line, Circular Arc, Elliptic Arc, Bézier Curve), paths or rings, they must be wrapped into high-level geometries types.

[C#]

//The following code shows to wrap a line segment into a polyline in C#

//Assume a line (line1 as ILine) is already created

object obj = Type.Missing;

ISegmentCollection segCollection = new PolylineClass() as ISegmentCollection;

segCollection.AddSegment((ISegment)line1, ref obj, ref obj);

 

//Set the spatial reference on the new polyline

//The spatial reference is not transfered automatically from the segments

IGeometry geom = segCollection as IGeometry;

geom.SpatialReference = spatialRef;

//Can now be used with ITopologicalOperator3 methods

 

[Visual Basic 6.0]
'How to wrap a line segment into a polyline in VB6
'Assume a line (pLine as ILine) is already created
Dim psc as ISegmentCollection Set psc = New Polyline psc.addsegment pline
'Set the spatial reference on the new polyline
'The spatial reference is not transfered automatically from the segments
dim pgeo as IGeometry
set pgeo = psc
set pgeo.SpatialReference = pMyspatialReference
'Can now be used with ITopologicalOperator methods

See Also

IGeometry Interface | IRelationalOperator Interface

Example

Share_a_line_segment

 


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