Seems like the last line in the error output in this bug report: *** Error in `/usr/bin/python': free(): invalid pointer: 0x00007ffc502179e8 ***
.. is related to issue 3090 upstream for mapnik: https://github.com/mapnik/mapnik/issues/3090 A fix seems to have been found, and a pull request has been made there: https://github.com/mapnik/mapnik/pull/3146 Ruben
