Hi Paul, Thanks for replying. My comments are inline.
On Mon, Nov 10, 2014 at 12:05 AM, Paul Norman <[email protected]> wrote: > On 11/9/2014 3:46 PM, Pulkit Bhuwalka wrote: > > 1. Download bulk data from OSM using API (This is a small region) > 2. Setup Postgres with PostGIS extension. > 3. Import data into PostGIS database using osm2pgsql > > I am not sure about the next step. What api should I use to query the > database? I suppose there exists some data access API which Mapnik and > other services use for drawing. > > The database you have created is a PostgreSQL database, and there are > libraries in most languages for connecting to one. > Sorry I wasn't clear. I understand that I can use a PostgreSQL driver from any language. I was wondering if there is an OpenStreetMap library/API which provides data access to the database. For instance where I can run queries like "return all nodes with a tag within a geometric bound". I thought there might be one since Mapnik and other services might need similar data access APIs. > Also, I don't quite understand the DB structure and the data encoding > within it. There are a few tables created by PostGIS (spatial_ref_sys etc.) > and a few tables created by OSM (planet_osm_*). I am unsure about the > relation between these tables. > > The point, line, and polygon tables contain points, lines and polygons > respectively. The roads table contains a subset of data for low-zoom > rendering and is more complicated to use. > Ok. So all roads and streets should be available in planet_osm_lines and planet_osm_polygons with "highway"/"landuse" or some similar column on. Is there a document which explains these? I want to use the data to 3D render roads, so probably I might need to use planet_osm_roads. > > > I recently also stumbled upon the Overpass API > <http://wiki.openstreetmap.org/wiki/Overpass_API> which seems to do > something similar. My requirements are actually pretty simple. I need some > simple querying to experiment with some rendering of my own. > > You should look at the documentation for whatever rendering library/server > you want to use. It's also worth reading through the documentation at > https://github.com/openstreetmap/osm2pgsql/tree/master/docs for more > information on osm2pgsql. > Ok. Yes, I'll take a look at that. I was just wondering if there is a data access API, similar to XAPI for editing the database that exists. > > _______________________________________________ > dev mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/dev > > Thanks so much for your help. Best, Pulkit -- Pulkit
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