Hi YongHeng<br>the result doesn't matter : your input polygons are not valid<br>Pascal<br><br><div class="gmail_quote">2009/4/10 LiN YongHeng <span dir="ltr"><<a href="mailto:bicealyh@gmail.com">bicealyh@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>Hello everyone,</div>
<div>I have a question about GEOSUnion().</div>
<div>I give value to g1 and g2 like below:</div>
<div>GEOSGeom g1 = "POLYGON ((1 3, 1 3, 1 6, 1 6, 1 3))" and GEOSGeom g2 = "POLYGON ((1 3, 1 3, 1 6, 1 6, 1 3))" , but if I make union operation like GEOSGeom g3 = </div>
<div>GEOSUnion(g1, g2), it give me result like "GEOMETRYCOLLECTION EMPTY". </div>
<div>Does anyone can tell me why?<br><br><br><br></div>
<div class="gmail_quote">2009/4/10 <span dir="ltr"><<a href="mailto:geos-devel-request@lists.osgeo.org" target="_blank">geos-devel-request@lists.osgeo.org</a>></span><br>
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<br>When replying, please edit your Subject line so it is more specific<br>than "Re: Contents of geos-devel digest..."<br><br><br>Today's Topics:<br><br> 1. Re: Boost License compatibility (Mateusz Loskot)<br>
2. Re: Boost License compatibility (Paul Ramsey)<br> 3. Re: Boost License compatibility (Mateusz Loskot)<br> 4. Re: Boost License compatibility (Greg Troxel)<br> 5. Re: Boost License compatibility (Mateusz Loskot)<br>
<br><br>----------------------------------------------------------------------<br><br>Message: 1<br>Date: Wed, 08 Apr 2009 22:20:56 +0100<br>From: Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>><br>
Subject: Re: [geos-devel] Boost License compatibility<br>To: GEOS Development List <<a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a>><br>Message-ID: <<a href="mailto:49DD1538.6050707@loskot.net" target="_blank">49DD1538.6050707@loskot.net</a>><br>
Content-Type: text/plain; charset=ISO-8859-1<br><br>Paul Ramsey wrote:<br>> Since you're talking about taking a small snippet of LGPL and putting<br>> it into a larger chunk of Boost, probably you will get no definitive<br>
> answer, since it hinges on whether your new combined result is a<br>> "derived work" (in which case it's LGPL) or not (in which case it can<br>> be Boost). The "safe" black-and-white answer is that combining<br>
> anything from a *GPL project with another compatibly-licensed project<br>> creates a *GPL resultant.<br><br>All this makes sense and seems to be best approach. Thanks!<br><br>Slightly changing my original question.<br>
Let's assume no code is copied.<br>Is it safe to "translate" or let's say rewrite some parts of<br>implementation of algorithms available in GEOS, using different<br>types, different idioms, different C++ constructions, etc.<br>
and license such work under the terms of Boost License?<br><br>Best regards,<br><br>p.s. I understand that the best answer is<br>probably "Ask your lawyer!", so sorry for bothering<br>if it's OT here.<br><br>
--<br>Mateusz Loskot, <a href="http://mateusz.loskot.net/" target="_blank">http://mateusz.loskot.net</a><br>Charter Member of OSGeo, <a href="http://osgeo.org/" target="_blank">http://osgeo.org</a><br><br><br>------------------------------<br>
<br>Message: 2<br>Date: Wed, 8 Apr 2009 14:31:55 -0700<br>From: Paul Ramsey <<a href="mailto:pramsey@opengeo.org" target="_blank">pramsey@opengeo.org</a>><br>Subject: Re: [geos-devel] Boost License compatibility<br>
To: GEOS Development List <<a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a>><br>
Message-ID:<br> <<a href="mailto:30fe546d0904081431h5cc15325kd478fb7abc81e6b@mail.gmail.com" target="_blank">30fe546d0904081431h5cc15325kd478fb7abc81e6b@mail.gmail.com</a>><br>Content-Type: text/plain; charset=ISO-8859-1<br>
<br>
Definitely an "ask your lawyer". Our feeling when porting JTS to C++<br>was that the port was still a "derived work" and should retain the<br>LGPL license of the original work. However, that was merely a feeling,<br>
I have no idea where the grey areas lie in things like algorithm<br>porting.<br><br>P.<br><br>On Wed, Apr 8, 2009 at 2:20 PM, Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>> wrote:<br>
> Paul Ramsey wrote:<br>
>> Since you're talking about taking a small snippet of LGPL and putting<br>>> it into a larger chunk of Boost, probably you will get no definitive<br>>> answer, since it hinges on whether your new combined result is a<br>
>> "derived work" (in which case it's LGPL) or not (in which case it can<br>>> be Boost). The "safe" black-and-white answer is that combining<br>>> anything from a *GPL project with another compatibly-licensed project<br>
>> creates a *GPL resultant.<br>><br>> All this makes sense and seems to be best approach. Thanks!<br>><br>> Slightly changing my original question.<br>> Let's assume no code is copied.<br>> Is it safe to "translate" or let's say rewrite some parts of<br>
> implementation of algorithms available in GEOS, using different<br>> types, different idioms, different C++ constructions, etc.<br>> and license such work under the terms of Boost License?<br>><br>> Best regards,<br>
><br>> p.s. I understand that the best answer is<br>> probably "Ask your lawyer!", so sorry for bothering<br>> if it's OT here.<br>><br>> --<br>> Mateusz Loskot, <a href="http://mateusz.loskot.net/" target="_blank">http://mateusz.loskot.net</a><br>
> Charter Member of OSGeo, <a href="http://osgeo.org/" target="_blank">http://osgeo.org</a><br>> _______________________________________________<br>> geos-devel mailing list<br>> <a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a><br>
> <a href="http://lists.osgeo.org/mailman/listinfo/geos-devel" target="_blank">http://lists.osgeo.org/mailman/listinfo/geos-devel</a><br>><br><br><br>------------------------------<br><br>Message: 3<br>Date: Wed, 08 Apr 2009 22:41:16 +0100<br>
From: Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>><br>Subject: Re: [geos-devel] Boost License compatibility<br>To: GEOS Development List <<a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a>><br>
Message-ID: <<a href="mailto:49DD19FC.7010107@loskot.net" target="_blank">49DD19FC.7010107@loskot.net</a>><br>Content-Type: text/plain; charset=ISO-8859-1<br><br>Paul Ramsey wrote:<br>> Definitely an "ask your lawyer". Our feeling when porting JTS to C++<br>
> was that the port was still a "derived work" and should retain the<br>> LGPL license of the original work. However, that was merely a feeling,<br>> I have no idea where the grey areas lie in things like algorithm<br>
> porting.<br><br>Right, I have similar feeling.<br><br>Thanks for help!<br><br>Best regards,<br>--<br>Mateusz Loskot, <a href="http://mateusz.loskot.net/" target="_blank">http://mateusz.loskot.net</a><br>Charter Member of OSGeo, <a href="http://osgeo.org/" target="_blank">http://osgeo.org</a><br>
<br><br>------------------------------<br><br>Message: 4<br>Date: Wed, 08 Apr 2009 18:02:48 -0400<br>From: Greg Troxel <<a href="mailto:gdt@ir.bbn.com" target="_blank">gdt@ir.bbn.com</a>><br>Subject: Re: [geos-devel] Boost License compatibility<br>
To: GEOS Development List <<a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a>><br>Message-ID: <<a href="mailto:rmiocv6ajnb.fsf@fnord.ir.bbn.com" target="_blank">rmiocv6ajnb.fsf@fnord.ir.bbn.com</a>><br>
Content-Type: text/plain; charset="us-ascii"<br><br><br>Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>> writes:<br><br>> The question is like this:<br>><br>
> Can I copy lines 10-30 from GEOS source file a.cpp to project X which<br>
> is licensed under the terms of Boost License?<br><br>If those lines are deemed to be non-trivial - and the rule of them is<br>that 10 or more lines are definitely non-trivial - then no, because you<br>have a derived work and can't distribute the LGPL code under the Boost<br>
License. If you read one line and write something to do a similar<br>algorithm but differently, almost certainly it's not a derived work and<br>the licnense of the inspirational work doesn't matter. The middle<br>
ground is hard and standard advice is not to skate near the edge of thin<br>ice.<br><br>> There is an existing code, project X licensed under Boost License.<br>> If I copy some work based on LGPL and include it in the X,<br>
> can I still distribute X under the terms of Boost License?<br><br>Definitely not.<br><br>>> It's pretty clear the boost people would reject including LPGL code<br>>> in boost, if that's what you are asking.<br>
><br>> And this is something that is not clear or better, not obvious to me.<br><br>>From reading their analysis of licenses, it seems clear to me that Boost<br>wants to allow proprietary use of boost. This is the same licensing<br>
goal as the BSDs, and it's different from the FSF goal.<br>-------------- next part --------------<br>A non-text attachment was scrubbed...<br>Name: not available<br>Type: application/pgp-signature<br>Size: 193 bytes<br>
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<br>------------------------------<br><br>Message: 5<br>Date: Wed, 08 Apr 2009 23:43:41 +0100<br>From: Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>><br>Subject: Re: [geos-devel] Boost License compatibility<br>
To: GEOS Development List <<a href="mailto:geos-devel@lists.osgeo.org" target="_blank">geos-devel@lists.osgeo.org</a>><br>Message-ID: <<a href="mailto:49DD289D.7070901@loskot.net" target="_blank">49DD289D.7070901@loskot.net</a>><br>
Content-Type: text/plain; charset=ISO-8859-1<br>
<br>Greg Troxel wrote:<br>> Mateusz Loskot <<a href="mailto:mateusz@loskot.net" target="_blank">mateusz@loskot.net</a>> writes:<br>><br>>> The question is like this:<br>>><br>>> Can I copy lines 10-30 from GEOS source file a.cpp to project X which<br>
>> is licensed under the terms of Boost License?<br>><br>> If those lines are deemed to be non-trivial - and the rule of them is<br>> that 10 or more lines are definitely non-trivial - then no, because you<br>
> have a derived work and can't distribute the LGPL code under the Boost<br>> License. If you read one line and write something to do a similar<br>> algorithm but differently, almost certainly it's not a derived work and<br>
> the licnense of the inspirational work doesn't matter. The middle<br>> ground is hard and standard advice is not to skate near the edge of thin<br>> ice.<br><br>Yes, this is best recommendation.<br><br>>>> It's pretty clear the boost people would reject including LPGL code<br>
>>> in boost, if that's what you are asking.<br>>> And this is something that is not clear or better, not obvious to me.<br>><br>> From reading their analysis of licenses, it seems clear to me that Boost<br>
> wants to allow proprietary use of boost. This is the same licensing<br>> goal as the BSDs, and it's different from the FSF goal.<br><br>Right, good point.<br><br>Thanks to all for help in understanding the issue!<br>
<br>Best regards,<br>--<br>Mateusz Loskot, <a href="http://mateusz.loskot.net/" target="_blank">http://mateusz.loskot.net</a><br>Charter Member of OSGeo, <a href="http://osgeo.org/" target="_blank">http://osgeo.org</a><br>
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<br>End of geos-devel Digest, Vol 78, Issue 7<br>*****************************************<br></blockquote></div><br>
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