Note you can also mess with the precision model JTS uses for calculations
(in part to workaround floating point arithmetic limitations).
Jody Garnett
On Tue, Mar 4, 2014 at 6:58 PM, Andrea Aime <[email protected]>wrote:
> On Tue, Mar 4, 2014 at 8:40 AM, Jody Garnett <[email protected]>wrote:
>
>> The libraries are not that different, GEOS is a port of JTS after all.
>> You may wish to ask on the JTS mailing list for details on how buffer and
>> centroid can be used.
>>
>
> Jody is spot on, aks on the JTS mailing list.
> And yeah, I can confirm it's not specific to WPS, here is a sample self
> contained program:
>
> import com.vividsolutions.jts.geom.Geometry;
> import com.vividsolutions.jts.geom.Point;
> import com.vividsolutions.jts.io.ParseException;
> import com.vividsolutions.jts.io.WKTReader;
>
>
> public class BufferUnbuffer {
>
> public static void main(String[] args) throws ParseException {
> Geometry point = new WKTReader().read(" POINT(12 42)");
> Geometry buffer = point.buffer(0.0001);
> Point centroid = buffer.getCentroid();
> System.out.println(centroid);
> }
> }
>
> The output is: POINT (12 41.99999999999999)
>
> If I had to venture a guess, this is due to Java using IEEE floating point
> numbers to the letter,
> whilst C compilers have them use whatever precision is available in the
> native CPU, and if memory
> serves me right, this results in more precision bits added to the
> computation (80bits vs 64bits)
>
> Hum... according to this page, Java can still perform calculations with 80
> bits, but the final
> representation is 64:
> http://en.wikipedia.org/wiki/Strictfp
>
> Cheers
> Andrea
>
>
>
> --
> == Our support, Your Success! Visit http://opensdi.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
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>
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>
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