Overpass turbo/Polygon Features

From OpenStreetMap Wiki
Jump to: navigation, search
Available languages — Overpass turbo/Polygon Features
· English · français

As OpenStreetMap doesn't have an intrinsic area data type, a heuristic/algorithm has to applied to determine whether a way is a Line or a Polygon. For overpass turbo and osmtogeojson I came up with the following (see here for a machine-readable JSON file of this table):

A way is considered a Polygon if

  1. it forms a closed loop
  2. and is not tagged area=no
  3. and at least one of the following conditions is true:

This is mostly based on the information found in the OSM-wiki (namely the presence and absence of the Mf way.png/Mf area.png symbols on the individual key-pages). I used taginfo's wiki database for this task.

Unfortunately, the wiki doesn't include any information about whether or not a tag is "categorizing" (such as landuse=*) or descriptive (such as name=*). Therefore, this algorithm includes my own understanding and opinion about this. For the same reason, this list is surely quite incomplete! Please inform me about more tags that could imply areas.