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Is it possible, say, for an independent developer to extract a list of "landmarks" (churches, museums, squares, ...) from OSM? (Question originally asked on IRC) |
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OpenStreetMap has millions of points of interest which will serve you well for this. These are "nodes" (points) each tagged with a set of keywords that indicate what each point is. For example, you might have a node with latitude 51.398, longitude -1.082, and tags So you need to get this data out of OSM. The first step is to identify which tags you're interested in. You might want, for example, everything tagged as a church: in other words, everything with There are two ways you can get this data out of the OSM database. One is by using Overpass, a separate API with a powerful query language which allows you to fetch data matching certain tags. The second is to download the OpenStreetMap data dump and filter it according to your needs. The data dump is called planet.osm. You can either download the whole world (really huge), or just an extract covering one country or state. Once you've downloaded it, you can use Osmosis or Osmfilter to extract the data for you, and output it into a file. Alternatively, you can load all the data into a local database with Osmosis or osm2pgsql, and then query the database for the features you want. 3
Especially in well-mapped parts of the world, points of interest may also be available as "areas" (closed sequences of nodes) instead of nodes. The tags are the same as you would find on nodes, but if you want a single latitude/longitude pair you need to calculate it from the area outline!
(10 Jul '10, 13:19)
Tordanik
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I posted a follow-up question that outlines the process of filtering specific data from a planet file. It may contain information useful to those interested in this topic. Also, I hope to get best practices on how to keep a POI database up-to-date once you have it set up, which is what my question is about. |
