[Java-collab] Introduction

[Markus Schneider]

As Andrea already knows, we're trying to keep the implementation effort as low as possible. Therefore, our approach is
not extending JTS, but using wrappers around JTS geometries, that can cope with simple and complex geometries:

- In case of a simple geometry (Point, LineString, Polygon), the wrapper is totally straightforward, e.g. calls to
#intersects() are just passed to JTS.
- For complex ones (e.g. curves with non-linear segments), the curve parameters are stored in the wrapper and
additionally, a linearized version is generated (represented using JTS) that is used to evaluate spatial predicates.

A major benefit of this approach is that it is also applicable to backends (e.g. PostGIS). We would store a linearized
version as a native PostGIS geometry (used for the topological predicates), and store a BLOB beside it that stores the
original curve segments and their parameters (only necessary when curve is not a linestring).

Obviously, this approach is restriced to operations on the footprint when dealing with 3D-geometries. But this is still
better than nothing :-) Getting a 3D-BBox-operator working should be manageble, though.

Best regards,
Markus

Andrea Aime wrote:
> Jody Garnett ha scritto:
>> Note I am serious about the Curve thing...
>> - It is strategic work - supporting the WKB format
>> - PostGIS / GEOS is starting moving on it
>> - JTS won't touch it so it is up to us :-D
>>
>> Mark Leslie and myself had some blog posts on it a couple months back;
>> another idea in search of time/funds/hapless volunteer :-D
>>
>> It also makes sense to walk before we can run; Curve is a smaller
>> problem then Geometry and is not one currently addressed?
> 
> Jody, DeeGree has this nice geometry library and they are interested
> is sharing the load on it as a whole. I believe it's well worth looking
> into.
> 
> Cheers
> Andrea
> 


-- 
Markus Schneider

l a t / l o n  GmbH
Aennchenstrasse 19           53177 Bonn, Germany
phone ++49 +228 184960       fax ++49 +228 1849629
http://www.lat-lon.de        http://www.deegree.org

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