Re: [jts-dev] Visual Center of Polygon

[Eric Angle <eric.lohner.angle@xxxxxxxxx>]

Hi Martin,

 

I was looking at the testDoubleDiamond() case here

 

https://github.com/geotools/geotools/blob/2ecdef12f99d8f46827e83bda536e67ed4969dd6/modules/unsupported/process-geometry/src/test/java/org/geotools/process/geometry/PolyLabellerTest.java

Polygon p = (Polygon) reader.read("POLYGON((0 5, 5 10, 10 6, 15 10, 20 5, 15 0, 10 4, 5 0, 0 5))");

and decided to try it out with the jts-ports PolyLabeller.getPolylabel(Geometry polygon, double precision).

Should I expect to get back either (5,5) or (15,5) plus or minus (roughly) precision?

I find

PolyLabeller.getPolylabel(p, 1)     = (5,5)

PolyLabeller.getPolylabel(p, 0.1)   = (14.727,4.961)

PolyLabeller.getPolylabel(p, 0.001) = (5.276,4.999)

In other words, the answer doesn't seem to improve with decreasing precision.

Any thoughts on what could be going on?

Thanks,

Eric

On Thu, Oct 25, 2018 at 12:39 AM Martin Davis <mtnclimb@xxxxxxxxx> wrote:

Yes.  And probably best implemented using the orientationIndex predicate.

On Wed, Oct 24, 2018, 8:42 PM Sandro Santilli <strk@xxxxxx> wrote:

On Wed, Oct 24, 2018 at 10:58:08AM -0600, Eric Angle wrote:

> Your suggestion of checking that all interior angles are less than 180
> makes sense to me.

Less than or equal to 180, I guess ?

--strk;
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