[GIS] Extract multiple admin levels from planet OSM

geojsonopenstreetmap

I am trying to create a multi-level choropleth map based on OSM data.

I need the outline/boundaries. I would like to do this from the command line if possible.

Here is what I think the steps should be.

  1. Download the planet OSM in XML or PBF format

  2. Extract the administrative boundaries for features with an admin level of 2, 4, 6 or 8. This is my current attempt:

    osmconvert planet-latest.osm.pbf -o=planet.o5m

osmfilter planet.o5m --keep-nodes= --keep-ways-relations="boundary=administrative and (admin_level=2 or admin_level=4 or admin_level=6 or admin_level=8)" > planet.osm

  3. Simplify the geometries to help with the file size without losing track of which features are "inside" other features.

  4. Convert the final product into GeoJSON.

I am struggling with #2 the most and it seems like the most important step.

If any other process I should try, please let me know.

Best Answer

Instead of downloading the xml/pbf file and filtering for the tags using osmfilter. you should use the overpass api that will give you filtered results. the api will search for filtered queries like admin_level=2 or admin_level=4 or admin_level=6 or admin_level=8 hence it will be much faster than any other method.

Here is an example that gives out admin_level = 2, http://overpass-turbo.eu/s/yv2

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