[geos-devel] Union problem

[Charlie Savage]

Hi Strk,

Comments below.

> Charlie, example.cpp, *and* unit tests, all keep using the C++ API.
> SWIG is using the C API instead, so you shouldn't expect things
> to work in the exactly same way.
> I would indeed discourage you from porting unit testing and example.cpp
> but rather find new tests which might be useful for CAPI in general.

Well, maybe you can help then.  What I would like is an example of two 
geometries and what the expected results would be for various operations 
like union, intersection, etc.  That way I can verify that the results 
returned through the C API are correct.

I guess I don't understand why you think example.cpp is a bad thing to 
look at.  I can see the geometries in their WKT format, and then I can 
see what the results are when different operations happen like union, etc.

Why would the union of the same two geometries be different depending on 
  whether you use the C API versus the C++ API?

Anyway, I'm happy to use any examples people have.  I don't think its 
viable for me to make up my own examples - I don't know what the results 
are supposed to look like.  Thus the tests would be useless.

> The unhappy messages you're seing are in fact very happy ones :)
> It's the new code handling robustness problems by trying different
> reduction or simplification. Your logs seems to reveal that a topology
> preserving simplification with a tolerance of 0.04 did it.
> Seems nice (you should look at results to actually tell if we like it)...

Sorry, don't understand.  Where is this tolerance set in doing a Union? 
     How do I control it through the C API?

And it then end its not happy - the results is a segmentation fault. 
That of course might be a bug in the SWIG bindings.

Charlie


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