The GEOS source tree on !GitHub is the official code repository To get the source from !GitHub, and start a configure: {{{ git clone https://github.com/libgeos/geos.git cd geos mkdir _build cd _build cmake .. make }}} To fork GEOS to !GitHub to modify and test new features, follow the guideline [https://help.github.com/articles/fork-a-repo Fork A Repo].