> I'd rather not re-implement Douglas-Peucker if someone has already done it. That depends on language you work in. For python, see https://github.com/jonasstein/scanaerial/blob/master/scanaerial_functions.py#L29 -- Darafei "Komяpa" Praliaskouski OSM BY Team - http://openstreetmap.by/ xmpp:me at komzpa.net mailto:me at komzpa.net