Hi! On Wed, May 17, 2017 at 08:22:09PM +0000, Andrey Novikov wrote: > I want to switch to pyosmium for data manipulation. I've read that it > nicely creates area objects from relations. But I didn't find in > documentation how to filter what relations and ways to process. I've read > how to filter them for my own purposes but I'm afraid that it processes all > relations to construct areas. I need to extract only a subset of them so I > do not want to waste time for processing of unwanted data.
Currently pyosmium/libosmium can only create all areas and you have to filter afterwards. The reason is that without creating all areas, old-style multipolygon relations (with tags on the outer ways instead of on the relations) can not be handled correctly. Now that old-style multipolygon relations are gone, I am working on changing this to allow filtering beforehand. That being said, the assembly of the multipolygon isn't that expensive. On my, admittedly beefy, server, it takes about 20 minutes for the whole planet to assemble all multipolygon (and boundary) relations. The bigger problem is the memory use. Until a better solution is available, another option for you might be to first use osmium-tool (http://osmcode.org/osmium-tool/) to filter out some relations by tags (http://docs.osmcode.org/osmium/latest/osmium-tags-filter.html) and then run this through your pyosmium program assembling the areas. Jochen -- Jochen Topf joc...@remote.org https://www.jochentopf.com/ +49-351-31778688 _______________________________________________ dev mailing list dev@openstreetmap.org https://lists.openstreetmap.org/listinfo/dev
