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===============
osm@spline Xapi
===============
Aim
============
We like to rewrite some parts of the XApi needed for our own application. Our
aim is not get a full implementation of the Xapi, but to answer only specific
requests, at low latency. For this subset of Xapi we want completly cover the
original api.
Requests
=============
This is a list of example requests, we want to optimize.
* xapi.spline.de/api/0.6/node[amenity=*]
* xapi.spline.de/api/0.6/node[highway=busstop]
* xapi.spline.de/api/0.6/node[bbox=-6,50,2,61]
* xapi.spline.de/api/0.6/node[amenity=hospital][bbox=-6,50,2,61]
a more formal description
-------------------------
We serve the node endpoint, but no others. We implment the tag based filtering,
for only one tag and a bounding box.
Basic setup
=============
Just execute bootstrap.sh which will install node and everything you need into
your local directory. If you don't trust us read the bootstrap.sh. If you have
node and npm installed you can just use "npm link src/nodejs/" to install all
the dependencies.
Database setup
=============
We use postgres 9.* with postgis 1.5. Postgres 9.0 is used becaus we need some
functions on hstores and postgis 1.5 is used for fancy geometry things.
To setup a database you first need a runing postgres 9.0 instance. I hope you know
how to do this.
Use
createdb osm
to create a database with name osm. Use
createlang plpgsql osm
to add plpgsql to your database. If you want to create a database user do so:
createuser <username>
Add hstore support for your database:
psql -d osm < /share/contrib/hstore.sql
Add postgis support for your database:
psql -d osm < /share/contrib/postgis-1.5/postgis.sql
Just do:
psql -d osm < /share/contrib/postgis-1.5/spatial_ref_sys.sql
Create the actual schema for osm data. For this step you need osmosis. If your
osmosis build is correct there should be a directory named pacakge/scripts where
you run:
psql -d osm < pgsql_simple_schema_0.6.sql
psql -d osm < pgsql_simple_schema_0.6_linestring.sql
Optional/stil to test:
psql -d osm < pgsql_simple_schema_0.6_action.sql
psql -d osm < pgsql_simple_schema_0.6_bbox.sql
For documentation on the schema read pgsql_simple.txt.
Import data from xml with:
osmosis --read-xml file="planet.osm.bz2" --wp host="localhost" password="TopSecretPassword" user="insertUserNameHere" database="osm"
Before or after import you may want to create a index or two. Examples below:
CREATE INDEX idx_nodes_tags ON nodes USING GIN(tags);
CREATE INDEX idx_nodes_tags ON nodes USING GIST(tags);
CREATE INDEX idx_ways_tags ON ways USING GIN(tags);
CREATE INDEX idx_ways_tags ON ways USING GIST(tags);
database shema (out dated)
================
We keep data in a highly specioaliced shema, that allows us to prevent tables
growing to big. And supports our requests at maximum speed.
| CREATE TABLE <tagname>:<tagvalue> (
| {bigint id}
| {longitude float4},
| {latitude float4},
| {object varchar}
| ) PRIMARY KEY id;
Implmentation
=============
Teilprobleme:
..............
1. Database import
mögliche Technologien:
* Osmosis- plugin
* selbst in python (Protobuf consumer, async pgsql schreiber)
2. Web API
..............
mögliche Technologien:
* node.js
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