[postgis] JTS vs Java2D

[mbdavis]

Good idea, Dave...

>From the JTS Technical Specifications:

"The Java Topology Suite (JTS) is a Java API that implements a core set of
spatial data operations using an explicit precision model and robust
geometric algorithms.  JTS is intended to be used in the development of
applications that support the validation, cleaning, integration and querying
of spatial datasets.  JTS attempts to implement the OpenGIS Simple Features
Specification (SFS) as accurately as possible."

JTS implements most methods of the SFS, including relate method, the binary
predicate methods (equals, disjoint, etc) , the spatial analysis methods
(intersection, union, buffer, etc).

Java2D is oriented toward operations for displaying 2D geometry, whereas JTS
is focussed on operations for performing spatial querying and analysis.  JTS
provides a richer Geometry model and a unified and complete framework for
querying and combining Geometries.  Java2D provides some of the same
functionality, but not in such a convenient framework, and with some
significant limitations on functionality (for instance, the ability to
determine spatial relationships is quite limited and mostly directed towards
testing points and rectangles, and the spatial combination methods such as
intersection are not implemented for all kinds of shapes).

Also, JTS implements a precision model and uses robust implementations of
spatial algorithms, to avoid problems with finite-precision numeric values.

Having said that, it should be possible to use Java2D methods to provide
some some simple spatial functionality such as polygon intersections.

Martin
-----Original Message-----
From: Dave Blasby [mailto:dblasby at refractions.net]
Sent: Wednesday, August 01, 2001 10:01 AM
To: postgis at yahoogroups.com; mbdavis at vividsolutions.com
Subject: Re: [postgis] Re: The Next Level(polygon clipping)


> I hope to make a version of JTS available on the Web in the next couple of
> months.
> 
> By the way, the Java2D Area *does* support holes, via the use of the
> subtract method.

Since we're talking about JTS, perhaps you could tell the group what it
is and how its different from Java 2D?

dave

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