A DataSource is a backend data datasource. These data datasources provide 
persistent storage for features.

OGR
===
The OGR datasource allows you to take any OGR datasource -- such as a shapefile,
PostGIS database, GML file, or other formats supported by OGR -- and use it
as a backend for a FeatureServer layer.

The OGR layer requires a 'dsn' property and a 'layer' property. In many cases, 
the layer is part of the DSN. An example OGR configuration might look like:

[myshape]
type=OGR
dsn=/home/example/myshape.shp
layer=myshape

Dependancies:
 * OGR
 * ogr Python bindings

DBM
===
The DBM datasource uses anydbm combined with pickle to store features in a file
on disk. It should work on any platform. A sample DBM configuration might
look like:

[scribble]
type=DBM
file=/home/example/scribble.db

Depending on the system on which it is running, the internals of this database
may be different. 

Dependancies:
 * None

BerkleyDB
=========
The BerkleyDB datasource is a subclass of the DBM datasource. It uses a 
BerkleyDB module for storage. The bsddb module is not available under OS X, 
however, this datasource should work on both Windows and Linux. It is 
recommended to use  this datasource instead of the DBM datasource when 
possible. 

Performance testing suggests that this datasource is approximately 25% faster
than the default anydbm module on Linux.

A sample BerkleyDB configuration might look like: 

[scribble]
type=BerkleyDB
file=/home/example/scribble.db

Dependancies:
 * working bsddb module

PostGIS
=======
The PostGIS datasource implements a direct connection to PostGIS (rather than
via OGR). This datasource requires dsn parameter and a layer parameter. It 
also accepts a geometry parameter, a string value representing the name of the 
geometry column, and a fid parameter, representing the name of the feature ID
column.

A sample PostGIS configuration might look like:

[mylayer]
type=PostGIS
dsn=dbname=mydata
layer=mylayer
fid=ogc_fid
geometry=wkb_geometry

Dependancies:
 * OGR
 * ogr Python bindings
 * psycopg

WFS
===
The WFS datasource implements read-only access to WFS servers. Required 
parameters are:
 * url
 * typename

A sample WFS layer configuration might look like:

[wfs]
type=WFS
url=http://zuluviz.sdsu.edu:8080/geoserver/wfs
typename=topp:states

Dependancies:
 * OGR
 * ogr Python bindings


Flickr
======
The Flickr datasource loads data from geotagged Flickr photos. Filtering
the results can be done by using any of the parameters listed at:

http://flickr.com/services/api/flickr.photos.search.html

For example, a flickr source limited to all photos which match all the 
tags 'mit', 'food', '2007' from the user with ID '56541240@N00'::

[flickr]
type=Flickr
user_id=56541240@N00
tags=mit,food,2007
tag_mode=all

By default, this only shows public photos. To grant the datasource access
to your non-public photos, you must fetch a 'read' permissions token from
the API. You can use the Flickr.py as a command line application to do this:

$ ./FeatureServer/DataSource/Flickr.py
Open the following URL in a browser:
http://flickr.com/services/auth/?api_key=[...]&perms=read&frob=[...]
Press enter when complete.

The result of this will be something like:

Your token is:

    721576-5d6044

Add the following line to a Flickr data source to complete configuration:

auth_token=721576-5d6044  

With this example, a Flickr datasource would look like:

[flickr]
type=Flickr
user_id=56541240@N00
auth_token=721576-5d6044