On 9/16/2015 12:31 AM, Stadin, Benjamin wrote:
I want to import planet.osm into a Postgresql db (I’m considering to
use imposm for the import). Once I have the whole planet imported, I
need to extract many small regions (say max 5km * 5km max). The area
is user-definable in my case, it can be any boundary with mentioned
maximum size.
I’m interested in how regional / metro extracts are done for the
cities provided at the OSM download page, what options there are
(especially performance-wise) and what I need to take care of
otherwise when extracting regions (missing relationships when
clipping, routing network issues, or else).
https://mapzen.com/data/metro-extracts and http://download.geofabrik.de/
are third party services. Both rely on standard tools, osmconvert in the
case of metro and osmosis in the case of geofabrik extracts. Both
require a predefined list of extracts to create.
Imposm is designed for creating a database for rendering and is lossy.
You could use it to provide the secondary services like shapefiles that
extract providers offer, but not extracts of the data itself.
The two options that come to mind for supporting user-defined extracts
are an osm3s (overpass) database or pgsnapshot database.
In the case of the latter, you'd do it without geometries or any tag
indexes, then use pyxapi, jxapi, cgimap, or osmosis to extract the data
for a bounding box.
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