Apologies, I provided a wrong URL. The code is at http://svn.gispython.org/svn/gispy/Shapely/branches/1.0/
Get it like $ svn co http://svn.gispython.org/svn/gispy/Shapely/branches/1.0/ Shapely-1.0 or use RapidSVN. To test the code without installing it, start a python interpreter from the Shapely-1.0 directory and check that an imported shapely comes from the correct file: $ cd Shapely-1.0 $ python >>> import shapely >>> shapely.__file__ 'shapely/__init__.pyc' Sean On Apr 6, 2009, at 2:51 AM, Pascal Leroux wrote: > Hi Sean. Glad to have helped ! I've tried to download r1225 but I'm > not used to work with Subversion. I've used RapidSvn but I've got > the error message "Could not open the requested SVN filesystem". Is > any login/password needed ? > > Pascal > > 2009/4/5 Sean Gillies <[email protected]> > Hi Pascal, thanks for tracking this down. Would you be willing to > download r1225 from the Shapely 1.0 branch? I've got a fix for the > various binary op/topology descriptors that keeps the reference counts > down to 2. > > http://svn.gispython.org/svn/Shapely/branches/1.0 > > On Apr 5, 2009, at 7:22 AM, Pascal Leroux wrote: > > > Hi Sean, > > > > I think I've found what's going wrong with the references. > > > > (the line numbers below correspond to the official release 1.0.11) > > > > I added in shapely/geometry/base.py, after line 266 (in __del__ > > method of the BaseGeometry) > > print "__del__ %x" % id(self) > > to see when a geometry instance is actually freed > > > > > > >>> from sys import getrefcount as grc > > >>> from shapely.geometry import Point > > >>> p=Point((0,0)) > > >>> grc(p) > > 2 > > > > Python documentation says that's ok to find +1 for the result that > is > > evaluated inside the function/method. So reference count is 1 > > > > >>> "%x" % id(p) > > 'b7e72e8c' > > >>> del p > > __del__ b7e72e8c > > > > As soon as the reference count equals 0, __del__ is called > > > > >>> p=Point((0,0)) > > >>> "%x" % id(p) > > 'b7e72e8c' > > >>> p.intersection > > <shapely.topology.BinaryTopologicalOp object at 0xb7d34cac> > > >>> grc(p) > > 3 > > >>> id(p)-id(p.intersection.context) > > 0L > > > > In the "__get__" method of class BinaryTopologicalOp (line 25, > > topology.c), > > self.context that was None, now equals my point p > > There's one more reference and the last statement above shows that > > the new > > reference is p.intersection.context > > > > >>> res = p.intersection(Point((9,9))) > > __del__ 94e428c > > >>> grc(p) > > 4 > > >>> id(p)-id(p.intersection.context) > > 0L > > > > A new "call" to "__get__" decrements AND re-increments : reference > > count doesn't change > > > > >>> id(p)-id(res.__p__) > > 0L > > >>> del p.intersection.context > > >>> grc(p) > > 3 > > > > When the function geom_factory is called, a new reference to the > > point is done > > "ob.__p__ = parent" (base.py, line 45) with "parent" that is my > > initial "p" > > > > >>> del res.__p__ > > >>> grc(p) > > 2 > > >>> del p > > __del__ b7e72e8c > > >>> > > > > When I explictely call "del res.__p__", the "p" reference count is > > OK (2-1) > > __del__ is now called after the last "del p" > > > > > > I think that this problem occurs for all the geometries (they are > > all (?) derived from BaseGeometry). > > And that explains the issue I posted last week and those of > yesterday. > > > > Do you think it's correct ? > > > > Pascal > > > > > > > > > > 2009/4/4 Pascal Leroux <[email protected]> > > Hi Sean, > > > > 2009/4/4 Sean Gillies <[email protected]> > > > > Hi Pascal, > > > > This cries out for a cascaded union, I think. Maybe we should have a > > 1.0.12 release. Still, the leaks trouble me. Statements like > > > > P = P.union(p) > > > > have caused me problems in the past. Probably a matter of held > > references? Any interest in digging into it? > > > > Of course I'm interested in finding what's going wrong. But I've > > using Python (and Shapely) for less than a year (my first mail to > > the mailing list was posted in last July) and I think my knowledge > > in Python is not big enough, especially for Python/C interface, to > > fix the issue. > > > > But I'm trying to get into your code and learn how Shapely works. I > > would be so sad to have to work again with C/libgeos. Once again, > > Shapely saves me time (thanks !) and I've taught my colleagues > > (Institut Géographique National, France) to use Python and Shapely _______________________________________________ Community mailing list [email protected] http://lists.gispython.org/mailman/listinfo/community
