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970

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5

Is there any geometry library available for Java? I'm looking for solution to get an intersection point(s) between two geometry objects.

+2  A: 

The package you should look at it java.awt.geom, which is part of the JDK.

In particular check out the java.awt.geom.Area class, which allows you to perform intersection operations between two Shapes.

EDIT

Finding the intersection points is non-trivial as far as I know, as you need to apply a different algorithm depending on the shapes you're analysing. For example, the algorithm for the intersection between two circles is given here, whereas the algorithm for calculating the intrsection between two Bezier curves is completely different (here).

EDIT 2

One suggestion: You could look into the PathIterator class, which returns a description of a shape's path as a sequence of segments. In particular check out FlatteningPathIterator, which will collapse any curves into multiple straight lines. Once your path has been reduced to straight lines, calculating the intersection points will be simple ... although obviously this is an approximation in cases where your shape contains curves.

Adamski
but the results are only true/false. I need the exacts intersection points
nanda
comment to EDIT: so far I know, once we know the equation of the path it is pretty straightforward to get intersection points. Maybe I will end up creating the library myself if there is no sophisticated solution out there.
nanda
See my 2nd edit.
Adamski
+1  A: 

http://edndoc.esri.com/arcobjects/9.2/Java/java/library_reference/Geometry/Geometry_overview.htm

Try this link this link contains full details about geomentry library.....

ratty
ESRI? $5000 just to get an intersection?
codekaizen
+1  A: 

JTS - Java Topology Suite - is the best.

http://www.vividsolutions.com/jts/jtshome.htm

It is free, fast, robust, and can handle degenerate intersections.

codekaizen
+1  A: 

JTS is your best free open source option. The method you are looking for in JTS is here

As far as commercial options, you have ESRI's Java JNI version of their ArcObjects library which has a very robust Geometry Library. The interface on ESRI's library is called ITopologicalOperator

If all you are trying to do is Geometric operations, JTS is your best option - it is an excellent library which has many ports to different languages. If, on the other hand, you are looking for an entire GIS system that does complex symbology, supports GIS workflows and multiuser editing, printing, etc etc, then I would start looking at the ESRI libraries.

rburhum
A: 

I found that JTS has changed hands, or changed home sites, or something. A newer version can be found here: http://maven.geotoolkit.org/com/vividsolutions/jts/1.10/

Edit: This might be its new home page: tsusiatsoftware.net/jts/main.html

Kendric Beachey