irale

Backend for a generic place-finding application using PostGIS and GeoDjango.

Dependencies

Minimum expected versions are:

postgresql 9.1
postgis 2.0.2
django 1.5b2
python-psycopg2 2.4.5
geojson 1.0.1

On a Debian Sid system,

# Install postgresql, python-psycopg2, and the dependencies
# required for building postgis
$ apt-get install postgresql python-psycopyg2 build-essential
libxml2-dev libproj-dev libjson0-dev xsltproc docbook-xsl
docbook-mathml libgdal-dev postgresql-server-dev-all

# Debian repositories only have postgis 1.5, so install it using
# the tarball from the site
$ http://download.osgeo.org/postgis/source/postgis-2.0.2.tar.gz
$ tar xf postgis-2.0.2.tar.gz
$ cd postgis-2.0.2
$ ./configure
$ make
$ make install

# Debian repositories only have Django 1.4, so use pip to install
# it in ~/.local
$ pip install --user git+git://github.com/django/django.git@1.5b2

# Get GeoJSON via pip
$ pip install --user geojson

# Make sure that your $PATH and $PYTHONPATH are set correctly
$ export PATH=$PATH:~/.local/bin
$ export PYTHONPATH=$PYTHONPATH:~/.local/lib

Database setup

First, get Postgresql to trust all local connections. For this, edit pg_hba.conf to contain these lines:

local   all             postgres                                trust
local   all             all                                     trust
host    all             all             127.0.0.1/32            trust
host    all             all             ::1/128                 trust

Create a superuser account with your UNIX login:

$ sudo -u postgres createuser -s $USER

Create a database call irale belonging to this new user:

$ createdb irale

Make it a spatial database for use with PostGIS:

$ psql irale
irale=# CREATE EXTENSION postgis;
irale=# CREATE EXTENSION postgis_topology;

Tell Django about your db user:

$ echo "user = '$USER'" >irale/localsettings.py

Generate the db schema:

$ python manage.py syncdb

Running

# Run the server on http://localhost:8000
$ python manage.py runserver

Optionally, get localtunnel to make the server accessible from the internet:

$ gem install localtunnel
$ localtunnel -k ~/.ssh/id_rsa.pub 8000

API endpoints

^id/(\d+)/$ - search by id. Returns a GeoJSON Feature.

^search/(\w+)/$ - search by key. Returns a GeoJSON FeatureCollection.

^search/(?P\w+)/(?P\w+)/$ - search by key and value. Returns a GeoJSON FeatureCollection.

^bounds/$ - search by bounding box; uses GET parameters like: ?nw= 23,34.4&se=239,51. Returns a GeoJSON FeatureCollection.

^around/$ - search by proximity to coordinate; uses GET parameters like: ?center=39.2,21&radius=200 (where radius is in meters). Returns a GeoJSON FeatureCollection.

^new/$ - add a new place; POST a JSON like this to it: {"name": "boar"}. Returns status code.

^edit/(\d+)/$ - edit an existing place by id. POST a JSON like this to it: {"name": "quire", "key": "type", "value": "bar"}. Returns status code.

^attach/(\d+)/$ - add a key/ value pair to an existing place by id. POST a JSON like this to it: {"key": "near", "value": "beach"}. Returns status code.

GeoJSON data format

All responses are returned in this format.

A GeoJSON Feature looks like:

{
    "type": "Feature",
    "properties": {
        "name": "Coors Field",
        "amenity": "Baseball Stadium",
        "popupContent": "This is where the Rockies play!"
    },
    "geometry": {
        "type": "Point",
        "coordinates": [-104.99404, 39.75621]
    }
}

A GeoJSON FeatureCollection looks like: