I couldn't reproduce the issue on a MacOSX system and on another Ubuntu system !!!
BUT, on the SAME Ubuntu system, - if I build libgeos with (g++ as a symbolic link to) g++4.2 : no problem, no empty geometry collection - if I build libgeos with (g++ as a symbolic link to) g++4.3 : the issue occurs ! (it was one of the differences between my two Ubuntu systems) With libgeos built with g++4.3, the issue desn't occur with a C program Is this problem known with g++4.3 on a linux system ? 2009/3/20 Pascal Leroux <[email protected]> > Sorry, I meant that, when you use Rtree, the "intersects" predicate is > always True for each polygon obtained with the "intersection" method of > Rtree. > > So if two polygons don't intersect each other, if their "minimum bounding > rectangle" intersects each other, the "intersects" predicate is True. > > 2009/3/20 Pascal Leroux <[email protected]> > > Hi all, >> >> With the geos library version 3.1, it seems that the "intersects" >> predicate (used with polygons) always returns True. For more than 135,000 >> couples of polygons (got with the "intersection" method of Rtree), I always >> got True but about 125,000 intersections were empty geometry collections. >> >> When I use the version 3.0.3, it doesn't happen : each time "intersects" >> returns True, the intersection is not empty. >> >> I couldn't reproduce this issue in C with version 3.1 : when >> GEOSintersects return 1 (True), the intersection returned by >> GEOSIntersection is not empty. >> >> All these tests have been done on Ubuntu with Shapely version 1.0.11 >> >> Here's a couple of polygons for which intersects return True with an empty >> intersection >> >> POLYGON ((599801.1221290760440752 2546550.0634658345952630, >> 599806.0258591863093898 2546538.0948937772773206, 599780.3041890829335898 >> 2546526.9730210378766060, 599777.5322963981889188 2546499.6322209336794913, >> 599807.2772084334865212 2546496.2815793519839644, 599804.4406587256817147 >> 2546476.6445081932470202, 599760.1544660580111668 2546483.7799901803955436, >> 599769.8198137159924954 2546536.2887050621211529, 599801.1221290760440752 >> 2546550.0634658345952630)) >> >> POLYGON ((599758.8006132490700111 2546478.1623347853310406, >> 599772.7430304150329903 2546474.0790138356387615, 599760.4723994010128081 >> 2546410.1387482765130699, 599767.0911384929204360 2546408.3941536685451865, >> 599762.7293910720618442 2546391.5474267113022506, 599740.1731945683714002 >> 2546396.7629298437386751, 599758.8006132490700111 2546478.1623347853310406)) >> >> Pascal >> > >
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