On Mon, May 27, 2013 at 9:17 PM, Justin Deoliveira <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.
Cheers
Andrea
--
==
GeoServer training in Milan, 6th & 7th June 2013! Visit
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
fax: +39 0584 1660272
mob: +39 339 8844549
http://www.geo-solutions.it
http://twitter.com/geosolutions_it
-------------------------------------------------------
------------------------------------------------------------------------------
Try New Relic Now & We'll Send You this Cool Shirt
New Relic is the only SaaS-based application performance monitoring service
that delivers powerful full stack analytics. Optimize and monitor your
browser, app, & servers with just a few lines of code. Try New Relic
and get this awesome Nerd Life shirt! http://p.sf.net/sfu/newrelic_d2d_may
_______________________________________________
GeoTools-Devel mailing list
GeoTools-Devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/geotools-devel
