Hi,
Yes, changing the tolerance affects the topology seriously. I tested this
class with different data sets. What is weird is for some data sets, it
works for a very small tolerance and for some not. Any alternative for this?
Cheers, Brian.
On Tue, Dec 3, 2013 at 12:21 AM, <
[email protected]> wrote:
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> Today's Topics:
>
> 1. Polygon difference (Brian Sanjeewa Rupasinghe)
> 2. Re: Polygon difference (Martin Davis)
> 3. extract inserted envelopes from strtree (andrea antonello)
> 4. Fwd: Polygon offset (Martin Davis)
> 5. DelaunayTriangulationBuilder snapping tolerance
> (Brian Sanjeewa Rupasinghe)
> 6. Point to polygon distance in specified directions
> (Michael Bedward)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 30 Nov 2013 13:41:50 +0000
> From: Brian Sanjeewa Rupasinghe <[email protected]>
> Subject: [Jts-topo-suite-user] Polygon difference
> To: [email protected]
> Message-ID:
> <
> caema-4gameevhzub-vmtdbnxiaqhrpzqb5quf08tdq9gt1u...@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> I have a small rectangles inside a bigger one with one side almost touching
> that of bigger rectangle. I need to get the difference which should be
> another rectangle wiith JTS difference() method. Once obtained the
> difference, output is not exactly a rectangle because
> vertices of the touching edge of smaller rectangle do not exist on the
> larger rectangle. Is there any possibility to clean the geometries so that
> the two touching lines will collapse and
> create new segments along that line with correct noding. I tried using
> GeometrySnapper class with computeOverlaySnapTolerance() method. But it
> did not work. Is there any other method to deal with this in JTS?
>
> Cheers, Brian
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 2
> Date: Sun, 1 Dec 2013 07:11:04 -0800
> From: Martin Davis <[email protected]>
> Subject: Re: [Jts-topo-suite-user] Polygon difference
> Cc: "[email protected]"
> <[email protected]>
> Message-ID:
> <
> cak2ens1vj8knq2txwbg+-no-0exrvzurbbeotrr0bqedez2...@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Would be helpful to see the WKT for this case and perhaps the expected
> output.
>
>
> On Sat, Nov 30, 2013 at 5:41 AM, Brian Sanjeewa Rupasinghe <
> [email protected]> wrote:
>
> > I have a small rectangles inside a bigger one with one side almost
> > touching that of bigger rectangle. I need to get the difference which
> > should be another rectangle wiith JTS difference() method. Once obtained
> > the difference, output is not exactly a rectangle because
> > vertices of the touching edge of smaller rectangle do not exist on the
> > larger rectangle. Is there any possibility to clean the geometries so
> that
> > the two touching lines will collapse and
> > create new segments along that line with correct noding. I tried using
> > GeometrySnapper class with computeOverlaySnapTolerance() method. But it
> > did not work. Is there any other method to deal with this in JTS?
> >
> > Cheers, Brian
> >
> >
> >
> >
> ------------------------------------------------------------------------------
> > Rapidly troubleshoot problems before they affect your business. Most IT
> > organizations don't have a clear picture of how application performance
> > affects their revenue. With AppDynamics, you get 100% visibility into
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> > Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics
> > Pro!
> >
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> > _______________________________________________
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> >
> >
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> An HTML attachment was scrubbed...
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> ------------------------------
>
> Message: 3
> Date: Mon, 2 Dec 2013 14:59:12 +0100
> From: andrea antonello <[email protected]>
> Subject: [Jts-topo-suite-user] extract inserted envelopes from strtree
> To: "[email protected]"
> <[email protected]>
> Message-ID:
> <
> cacck5jpeq5najqu97b09vlpxjg8toaa2pn+wcrgpepo95tg...@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hello,
> I am trying to understand if there is a way to get the list of envelopes
> that were used to insert items in a STRtree, but while I see a way to get
> the itemstree I can't find one to get the itemBoundables list.
>
> Any idea?
>
> Thanks,
> Andrea
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 4
> Date: Mon, 2 Dec 2013 11:29:01 -0800
> From: Martin Davis <[email protected]>
> Subject: [Jts-topo-suite-user] Fwd: Polygon offset
> To: "[email protected]"
> <[email protected]>
> Message-ID:
> <CAK2ens0maXAt2huOznTNKvZkdqGu81cR=
> [email protected]>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Brian, please send these questions to the JTS list so all can share.
>
> Yes, setQuadrantSegments is irrelevant if JOIN_MITRE is used.
>
> For an explanation of mitre limit see the Javadoc:
>
> http://tsusiatsoftware.net/jts/javadoc/com/vividsolutions/jts/operation/buffer/BufferParameters.html#setMitreLimit(double)
>
>
> On Sun, Dec 1, 2013 at 8:44 AM, Brian Sanjeewa Rupasinghe <
> [email protected]
> > wrote:
>
> > Hi Martin,
> >
> > In the code i sent for setting parameters in buffering, i suppose
> BufP.setQuadrantSegments(1)
> > does not make any sense for Join_Meter style . What is meant by setting a
> > value to Default_Meter_Limit? Will it be more the value, more pointing at
> > corners??
> >
> > Cheers, Brian
> >
> >
> > On Thu, Nov 28, 2013 at 10:10 PM, Brian Sanjeewa Rupasinghe <
> > [email protected]> wrote:
> >
> >> Here is the method and the polygon i used with a +- 20 m distance.
> >>
> >> public static Geometry bufferPlusMinus (Geometry g, double dst1, double
> >> dst2)
> >> {
> >> BufferParameters BufP = new BufferParameters();
> >> BufP.setEndCapStyle(3);
> >> BufP.setJoinStyle(2);
> >> BufP.setQuadrantSegments(1);
> >> BufferBuilder Buffb = new BufferBuilder(BufP);
> >> Geometry BuffG = Buffb.buffer(g, dst1);
> >> Geometry fp = Buffb.buffer(BuffG, dst2);
> >> return fp;
> >> }
> >>
> >>
> >>
> >>
> >> POLYGON ((852.0508353104653 79.66036245972747, 785.3441701464214
> >> -13.474425749638762, 721.4579830330817 -14.427950930434887,
> >> 718.7632379569188 10.092344825531626, 718.535947988926 20.8108253483052,
> >> 739.5010955848701 12.351204388538228, 734.8751753004104
> 4.721699044367739,
> >> 776.4081693414112 6.153871252678144, 785.3441701464214
> 12.270754131856343,
> >> 831.0856877145211 70.0973126791213, 814.1664457949871 71.5685511069069,
> >> 803.8677768004884 81.49941049445935, 852.0508353104653
> 79.66036245972747))
> >>
> >>
> >>
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 5
> Date: Mon, 2 Dec 2013 22:50:56 +0000
> From: Brian Sanjeewa Rupasinghe <[email protected]>
> Subject: [Jts-topo-suite-user] DelaunayTriangulationBuilder snapping
> tolerance
> To: [email protected]
> Message-ID:
> <
> caema-4irrhwbrq9zcjufabe_owixi_sbkc7s4q+f1bi+bsv...@mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
>
> I use DelaunayTriangulationBuilder class to run triangulation between
> polygons and lines (about 2500 geometries) with lines used as constraint
> edges. Initially i set the tolerance to a smaller value (0.001). For this
> value, triangulation does not run. However, when i increased it to 3.1, the
> triangulation executed. This tolerance is for snapping according to JTS
> API. I need to know what happens when the tolerance is increased. Will it
> affect triangulation result? According to API, i suppose it is not, but to
> deal with robustness issues. Further clarification is appreciated.
>
> Cheers, Brian
> -------------- next part --------------
> An HTML attachment was scrubbed...
>
> ------------------------------
>
> Message: 6
> Date: Tue, 3 Dec 2013 11:21:19 +1100
> From: Michael Bedward <[email protected]>
> Subject: [Jts-topo-suite-user] Point to polygon distance in specified
> directions
> To: "[email protected]"
> <[email protected]>
> Cc: Trent Penman <[email protected]>
> Message-ID:
> <
> cacjvtdou4jseh+sxl-otmrdybbku_eb-8w-cv7a+9e84aft...@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hi Martin,
>
> The following is a general algorithm query rather than a specific JTS
> question - hope that's ok.
>
> I have a set of polygons which represent urban areas within a
> fire-prone landscape. There are about 5000 polygons varying widely in
> area, spatial extent, number of vertices and boundary complexity.
>
> I have the task of creating a regular grid of sample points within the
> surrounding landscape and, for each point, determining the distance to
> the nearest polygon within each of eight compass segments (ie. N to
> NE, NE to E...). The results only need to be expressed as categorized
> values based on a small number of distance cut-points.
>
> I've been trying to nut out something other than a brute force
> approach to this without much success so far. One of the possibly less
> brutish approaches I've thought of involves the following:
>
> 1. Split up the urban polygons by intersecting them with a regular
> lattice, create PreparedGeometry objects for the resulting parts and
> put them into an STRtree.
>
> 2. Construct a sampling template made up of polygons representing the
> compass segments, each split according to the distance cut-points
> (looking a bit like a dart board), possibly using a custom
> CoordinateSequence to have vertex coordinates calculated on the fly
> based on the centre coordinate.
>
> 3. For each sample point location:
> For each compass segment:
> For inner to outer segment part:
> Query the spatial index with the segment part envelope
> and, if any urban polygons are returned, test for
> intersection.
>
> I'm sure there must be a better way. Any suggestions or comments will
> be gratefully accepted.
>
> Michael
>
>
>
> ------------------------------
>
>
> ------------------------------------------------------------------------------
> Rapidly troubleshoot problems before they affect your business. Most IT
> organizations don't have a clear picture of how application performance
> affects their revenue. With AppDynamics, you get 100% visibility into your
> Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics
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> ------------------------------
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> End of Jts-topo-suite-user Digest, Vol 48, Issue 1
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>
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