[boost] [geometry] [polygon] What's the relationship?

Could someone please explain the relationship, if any, betweeen these two libraries? They seem to cover similar domains. Do they interoperate? Is one better than the other for certain kinds of problems? Was Boost.Polygon once called the Geometry Template Library, as suggested by the BoostCon 2009 slides? Boy, that's confusing. Lastly, could we get these libraries' documentation to mention one another and explain the information I'm asking for? Thanks in advance for answering. -- Dave Abrahams BoostPro Computing Software Development Training http://www.boostpro.com Clang/LLVM/EDG Compilers C++ Boost