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On 11/9/2014 3:46 PM, Pulkit Bhuwalka wrote:<br>
<blockquote
cite="mid:CAPYxK1UygSvuvk0WcpsiVM_dfzFy30vqNtHW6rn6mcPDiukeBA@mail.gmail.com"
type="cite">
<div dir="ltr">1. Download bulk data from OSM using API (This is a
small region)
<div class="gmail_signature">2. Setup Postgres with PostGIS
extension.</div>
<div class="gmail_signature">3. Import data into PostGIS
database using osm2pgsql</div>
<div class="gmail_signature"><br>
</div>
<div class="gmail_signature">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.</div>
</div>
</blockquote>
The database you have created is a PostgreSQL database, and there
are libraries in most languages for connecting to one.
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<div class="gmail_signature">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.</div>
</div>
</blockquote>
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.<br>
<br>
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<div class="gmail_signature">I recently also stumbled upon the <a
moz-do-not-send="true"
href="http://wiki.openstreetmap.org/wiki/Overpass_API">Overpass
API</a> 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.</div>
</div>
</blockquote>
You should look at the documentation for whatever rendering
library/server you want to use. It's also worth reading through the
documentation at
<a class="moz-txt-link-freetext" href="https://github.com/openstreetmap/osm2pgsql/tree/master/docs">https://github.com/openstreetmap/osm2pgsql/tree/master/docs</a> for more
information on osm2pgsql.<br>
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