Below you’ll find the build instructions I packed also into the downloads. I just post it here to minimize chance for it to get lost.
It allows you to build libgeos for your platform and relatively link the binaries to each other. Put them in the DLL folder of shapely. Shapely should support Python3.x now. No need to adapt it yourself: https://pypi.python.org/pypi/Shapely. With these instructions it’s not much work to maintain the lib. I can do it. You can help me. (Especially the linux part). Deal?
EDIT: I can imagine Blender devs not really want to include a geometry library if it’s not used by a built in operator. They anyway want to keep the size of Blender as small as possible. That means: Only if libgeos should become more important for several parts of Blender they would integrate it.
Linux & MacOs:
Install CMake if you haven’t. Build libgeos according to their documentation:
Modify the rpath attribute of libgeos_c.dylib/.so in order to link libgeos.dylib/.so
with a relative path:
install_name_tool -change “/absolute/path/to/your/libgeos.3.4.0dev.dylib” “@loader_path/libgeos.3.4.0dev.dylib” libgeos_c.dylib
–> this tells libgeos_c.dylib (which can be called from python) where it can find the c++ library “libgeos.3.4.0dev.dylib”.
so you do this with “libstdc++.6.dylib” and “libSystem.B.dylib” too and it should work
LINUX: replace install_name_tool with chrpath and dylib with so.
on a mac: install_name_tool
on linux: sudo apt-get install chrpath, if you don’t already have it
install Visual Studio: follow the libgeos build instructions:
(nmake typically is loacated somewhere like C:\Programs(x86)\Visual Studio\VC\bin)
set your path’s: http://jahboite.co.uk/blog/2009/01/path-env-var-setx.html
shapely automatically sets the environment variable on windows from within python
to include this DLLs directory to its path: no rpath alike steps necessary