Sorry I haven't responded sooner. I've been trying to help Stefan squish bugs for our next OpenJUMP release. :]
Jody wrote: "The step I am trying to interest Landon in working on (custom Geometry Extensions) would more be a proof of concept that we could pass over to Martin if it works; since the operations (ie the back end) would still be linear there is a chance it is within the scope of JTS." I'm on board for working on some type of 2D curve support in Geotools. I'll need a couple more weeks before I can start. I'd like to get the OJ release out before I start something new. Jody wrote: "Make a couple more Geometry subclasses that match these data structures (CurveString,CompoundCurve,CurvePolygon); implement them as wrappers around the traditional JTS LineString and Polygon; and lazily create this object as needed. We can experiment with the current approach (using the same 128 side circles as buffer) or look at using the Percision model for a perfect representation." I'm hesitant to hack curved geometries onto JTS. I almost wonder if it would be better to start with a "clean" implementation. If you search the JTS archives you'll find an extensive thread in which many of the problems of adding curve support to JTS are discussed. I think this approach might be better: - Add curves to a geometry library without worrying about JTS. - Add lines to the same geometry library. The interface for these line objects will play nice with the curves, but could be implemented by JTS objects underneath. I would make this suggestion: After the next OJ release I'll add an unsupported module to Geotools to work with route stationing. I'll focus on the needed geometry to support this module first. I'm thinking of three or four classes/interfaces to get started: - LinearGeometry (Interface) - CircularArc (Class Implements LinearGeometry) - StraightLine (Class Implements LinearGeometry) We can store CircularArc and StraightLine objects using WKT. This would just be a starting point, and I'm not sure how it would fit with the code Jody is already working on. However, I think it would give us a shot at "WKT backed" curves without immmediately worrying about integration with JTS. I'm afriad a curve system that fits with existing JTS code may not be as graceful as one that focuses on doing curves correctly, regardless of JTS. SS On Mon, Mar 9, 2009 at 5:25 PM, Jody Garnett <jody.garn...@gmail.com> wrote: > Not sure I will CC him on the possibility. > From my standpoint I have gone for beer with Martin and talked about what it > would take to get curve supported (that is where my half a million number > comes from). The way to break the problem up into front end geometry and > back end operations (which we would choose from based on coordinate > reference system) comes from discussions with Martin and Adrian Custer. > So the plan is sound; just no way to fund it at this time. > > As for this short term hacking - I will talk to Martin when this WKTParser / > WKBParser is finished and see if he wants the code (he may since he supports > EWKT / EWKB in order to match PostGIS and this is what PostGIS is now > doing). > As written it is in a format that Martin would probably accept - since it > produces normal JTS LineString and Polygons. > The step I am trying to interest Landon in working on (custom Geometry > Extensions) would more be a proof of concept that we could pass over to > Martin if it works; since the operations (ie the back end) would still be > linear there is a chance it is within the scope of JTS. > Jody > > On Tue, Mar 10, 2009 at 11:06 AM, Michael Bedward > <michael.bedw...@gmail.com> wrote: >> >> 2009/3/10 Jody Garnett <jody.garn...@gmail.com>: >> > - Work on Geometry implementations as per my previous email (benifit >> > here would be less memory use and "pixel perfect" rendering). >> > >> >> Has anyone chatted to Martin Davis about that option ? I know that >> previously he's said there are no plans to support curves in JTS but >> that was a while ago. >> >> Michael > > > ------------------------------------------------------------------------------ > > _______________________________________________ > Geotools-devel mailing list > Geotools-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-devel > > ------------------------------------------------------------------------------ Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are powering Web 2.0 with engaging, cross-platform capabilities. Quickly and easily build your RIAs with Flex Builder, the Eclipse(TM)based development software that enables intelligent coding and step-through debugging. Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com _______________________________________________ Geotools-devel mailing list Geotools-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-devel
