Micheal Bedward had a utility class for working with Curves (used in the docs
below). As such it can hold a method to generate curves in a consistent
fashion.
http://docs.geotools.org/latest/userguide/library/jts/geometry.html#arcs-circles-and-curves
--
Jody Garnett
On Wednesday, 29 May 2013 at 11:31 PM, Justin Deoliveira wrote:
>
>
>
> On Tue, May 28, 2013 at 8:00 AM, Andrea Aime <andrea.a...@geo-solutions.it
> (mailto:andrea.a...@geo-solutions.it)> wrote:
> > On Mon, May 27, 2013 at 9:17 PM, Justin Deoliveira <jdeol...@opengeo.org
> > (mailto:jdeol...@opengeo.org)> wrote:
> > > Sounds like a good approach to me. So to clarify, are you planning on
> > > taking the Circle/Arc code from the gml3 module and putting that in the
> > > api module?
> >
> > Yes, and wrap it in a CircularString class that hides the circular nature
> > to the unprepared observer.
> > However, Jody's comments in yesterday's meeting about paying attention to
> > linearization prompted me to
> > look into the linearization code in WKTReader2, in particular the
> > circularSegmentize methods.
> >
> > They do work using a different approach as Circle, in particular Circle
> > guarantees a fixed distance
> > between linearized and original geometry, whilst WKTReader2 is based on the
> > "segments per quadrant"
> > approach, which is the same approach postgis uses.
> > Jody was warning about linearizing valid geometries, and ending up with
> > invalid ones, which I believe
> > can happen having two concentric arcs, starting and ending at different
> > angles, and having a radius
> > that's very close to each other.
> > My understanding is that to avoid topologic issues the sampling points
> > should be chosen at the
> > same angles in both arcs, something that the "max distance" approach does
> > not necessarily guarantees,
> > yet, the code in WKTReader2 does not guarantee that either.
> >
> > I guess a mix of the two would be needed, pick a starting number of
> > quadrants, double them until the max distance
> > is lower than the expected one, and then perform a sampling that follows
> > fixed angles set starting from zero
> > instead of the arc start (obviously, still respecting the start and end
> > points, which would happen to be at less
> > than the chosen sampling angle from the first fixed sampling point.
> >
> > If I go this way I guess I'll have to write my own linearization code, not
> > the end of the world I guess, but I won't
> > need the Circle/Arc classes from GML anymore.
> >
> Do you see a chance to consolidate? It would be nice to use a single set of
> curve classes located in api or main and have the gml encoding work off of
> them. It isn't clear to me if the GML model is compatible with the one you
> are proposing.
>
> > Cheers
> > Andrea
> >
> >
> > --
> > ==
> > GeoServer training in Milan, 6th & 7th June 2013! Visit
> > http://geoserver.geo-solutions.it (http://geoserver.geo-solutions.it/) for
> > more information.
> > ==
> >
> > Ing. Andrea Aime
> > @geowolf
> > Technical Lead
> >
> > GeoSolutions S.A.S.
> > Via Poggio alle Viti 1187
> > 55054 Massarosa (LU)
> > Italy
> > phone: +39 0584 962313 (tel:%2B39%200584%20962313)
> > fax: +39 0584 1660272 (tel:%2B39%200584%201660272)
> > mob: +39 339 8844549 (tel:%2B39%20%C2%A0339%208844549)
> >
> > http://www.geo-solutions.it
> > http://twitter.com/geosolutions_it
> >
> > -------------------------------------------------------
>
>
> --
> Justin Deoliveira
> OpenGeo - http://opengeo.org
> Enterprise support for open source geospatial.
>
>
>
> ------------------------------------------------------------------------------
> Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET
> Get 100% visibility into your production application - at no cost.
> Code-level diagnostics for performance bottlenecks with <2% overhead
> Download for free and get started troubleshooting in minutes.
> http://p.sf.net/sfu/appdyn_d2d_ap1
>
> _______________________________________________
> GeoTools-Devel mailing list
> GeoTools-Devel@lists.sourceforge.net
> (mailto:GeoTools-Devel@lists.sourceforge.net)
> https://lists.sourceforge.net/lists/listinfo/geotools-devel
>
>
------------------------------------------------------------------------------
Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET
Get 100% visibility into your production application - at no cost.
Code-level diagnostics for performance bottlenecks with <2% overhead
Download for free and get started troubleshooting in minutes.
http://p.sf.net/sfu/appdyn_d2d_ap1
_______________________________________________
GeoTools-Devel mailing list
GeoTools-Devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-devel
