[turn] judge the relationship between two geometries in ArcGIS

[ turn ]ArcGIS Two of them Geometry The relationship between

Operate two Geometry when , The common interface is ITopologicalOperator, such as clip,Intersect,Union,cut etc. .

When judging two Geometry Topological relationship between , use IRelationalOperator , It has Contains、Crosses、Disjoint、Equals、Overlaps、Within、Touches Other methods .

Example :

 

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1. ITopologicalOperator sourcePolygon= (ITopologicalOperator)outerPolygon;  
2. IPolygon resultPolygon = (IPolygon)sourcePolygon.Difference(cutPolygons);  

 

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1. IRelationalOperator re = (IRelationalOperator)outerPolygon;  
2. if (!re.Contains(inPolygon))  
3. {  
4.     throw new Exception("abcdefg");  
5. }  

 

Pay attention to , If the two involved in the operation Geometry When the object is not a simple object ,( notes 1:Simple object , See the picture below )( notes 2: It can be used ITopologicalOperator Interface IsSimple Function to judge )( notes 3: When using IPointCollection And other interfaces Geometry This is often the case with objects ), The operation may be wrong , And can't get the desired result , At this time, it needs to be handled :

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1. ((ITopologicalOperator)outerPolygon).Simplify();  

Definition and processing of simple objects

 

 

attach 1:ITopologicalOperator Some functions of :

Method name	explain
Boundary	Boundary of geometry object
Buffer	Perform buffer space topology operations on geometry objects
Clip	Perform clipping space topology operations on geometry objects
ConstructUnion	Efficiently merge multiple enumerated geometric objects and a single geometric object into a single geometric object , This is very efficient for merging a large number of geometric objects
ConvexHull	Building convex shapes of geometric objects
Cut	Cutting geometric objects
Difference	One geometry subtracts the part it intersects with another geometry
Intersect	The intersection of two geometric objects with the same dimension
Simplify	Make the topology of geometric objects consistent
SymmetricDifference	Symmetric difference subtracts the intersection of two geometries from the union of two geometries
Union	Merge two geometric objects with the same dimension into a single geometric object

 

The illustration :

http://www.gisjc.com/a/ArcGIS_Engine/2010/0425/239.html

 

attach 2:IRelationalOperator Some relationship types :

 

Type of relationship	describe
Contains	Determine whether a figure contains another figure
Within	Determine whether a figure is contained by another figure .
Crosses	Judge whether two figures intersect inside the figure with less dimension
Disjoint	Judge whether there are no similarities between the two figures
Equals	Judge whether the two figures are of the same type and whether the points on the plane are in the same position . If the return value is true , Then they should contain （Contains） Another figure is also included by another figure (Within).
Overlaps	Judge whether the intersection of two figures has the same dimension as one of them , And their intersection cannot be equal to any of them . This method uses only two Polyline Between or two Polygon Between .
Touch	Judge whether the boundaries of two figures intersect , If the intersection of two figures is not empty , But the intersection of the two figures is empty , The return value is true .