On Tue, Jun 12, 2018 at 10:57 PM Mateusz Konieczny <matkoni...@tutanota.com> wrote: > > > > > 12. Jun 2018 13:22 by marc.ge...@gmail.com: > > How do people in GIS know how many square meter of forest there is in > a country based on OSM-data ? > > > I would start from something like: total area of area covered by > > landuse=forest and natural=wood > > after excluding very small areas. > >
won't work, see e.g. https://www.openstreetmap.org/search?query=waasmunster#map=16/51.1215/4.0932&layers=N that's not a forest, that are a lot of private gardens with trees in it. > > Is the data suited for that ? > > > Depends on (a) where (b) what kind of accuracy is needed, forest in many > regions > > are unmapped or partially mapped. > > > > How can I find those places with OSM data ? > > > What you exactly want to find? A forest is a place where you can walk, ride, cycle. Not someones private backyard. Our government talks often about there is so many square meter of forest in Belgium. It's not sufficient to subtract all small areas, you need to subtract somehow everything that is not a forest (see above) > > > > I thought I had an answer for all the above questions when > natural=wood, landuse=forest, landcover=trees where used "properly". > > > No, you cant. As there are conflicting tagging methods If everything was "properly" mapped with those 3 tags I could come up with an algorithm. Not with the current mess of course. _______________________________________________ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
