http://www.nextbus.com/xmlFeedDocs/NextBusXMLFeed.pdf
http://webservices.nextbus.com/service/publicXMLFeed?command=agencyList
Obtain a list of available transit agencies.
<?xml version="1.0" encoding="utf-8" ?>
<body copyright="All data copyright agencies listed below and NextBus Inc 2014.">
<agency tag="actransit" title="AC Transit" regionTitle="California-Northern"/>
<agency tag="art" title="Asheville Redefines Transit" regionTitle="North Carolina"/>
<agency tag="sf-muni" title="San Francisco Muni" shortTitle="SF Muni" regionTitle="California-Northern"/>
</body>
http://webservices.nextbus.com/service/publicXMLFeed?command=routeList&a=<agency_tag>
Obtain a list of routes for a given agency. The agency is specified by the "a" parameter in the query string. The tag for the agency is obtained from the agencyList command.
<?xml version="1.0" encoding="utf-8" ?>
<body copyright="All data copyright San Francisco Muni 2014.">
<route tag="F" title="F-Market & Wharves"/>
<route tag="J" title="J-Church"/>
<route tag="KT" title="KT-Ingleside/Third Street"/>
</body>
http://webservices.nextbus.com/service/publicXMLFeed?command=routeConfig&a=<agency_tag>&r=<route tag>
Obtain a list of routes for a given agency. The route is optionally specified by the "r" parameter. The tag for the route is obtained using the routeList command. If the "r" parameter is not specified, all routes for the agency are returned, limited to 100 routes per request.
<?xml version="1.0" encoding="utf-8" ?>
<body copyright="All data copyright San Francisco Muni 2014.">
<route tag="F" title="F-Market & Wharves" color="555555" oppositeColor="ffffff" latMin="37.7625199" latMax="37.8085899" lonMin="-122.43487" lonMax="-122.39345">
<stop tag="5184" title="Jones St & Beach St" lat="37.8072499" lon="-122.41737" stopId="15184"/>
<stop tag="3092" title="Beach St & Mason St" lat="37.80741" lon="-122.4141199" stopId="13092"/>
<stop tag="3095" title="Beach St & Stockton St" lat="37.8078399" lon="-122.41081" stopId="13095"/>
<direction tag="F__OBCTRO" title="Outbound to Castro Station via Downtown" name="Outbound" useForUI="true">
<stop tag="5184" />
<stop tag="3092" />
<stop tag="3095" />
</direction>
<direction tag="F__IBCTRO" title="Inbound to Fisherman's Wharf via Downtown" name="Inbound" useForUI="true">
<stop tag="3311" />
<stop tag="5687" />
<stop tag="5691" />
</direction>
<path>
<point lat="37.76252" lon="-122.43487"/>
<point lat="37.76267" lon="-122.4352"/>
<point lat="37.76396" lon="-122.43332"/>
<point lat="37.76569" lon="-122.43114"/>
<point lat="37.76726" lon="-122.42915"/>
</path>
<path>
<point lat="37.78036" lon="-122.41261"/>
<point lat="37.7821" lon="-122.4104"/>
<point lat="37.78389" lon="-122.40814"/>
<point lat="37.7856499" lon="-122.40589"/>
</path>
<path>
<point lat="37.7856499" lon="-122.40589"/>
<point lat="37.7875299" lon="-122.40352"/>
<point lat="37.78861" lon="-122.40216"/>
<point lat="37.79094" lon="-122.39919"/>
</path>
</route>
</body>
http://webservices.nextbus.com/service/publicXMLFeed?command=predictions&a=<agency_tag>&r=<route tag>&s=<stop tag>
Obtain predictions associated with a particular stop. There are two ways to specify the stop: 1) using a stopId or 2) by specifying the route and stop tags.
http://webservices.nextbus.com/service/publicXMLFeed?command=predictionsForMultiStops&a=<agency_tag>&stops=<stop 1>&stops=<stop 2>&stops=<stop 3>
To obtain predictions associated with multiple stops use the "predictionsForMultiStops" command. The stops are specified by using the "stops" parameter multiple times.
http://webservices.nextbus.com/service/publicXMLFeed?command=schedule&a=<agency_tag>&r=<route_tag>
Obtain the schedule information for a route. The route is specified by the "r" parameter. The tag for the route is obtained using the routeList command.
http://webservices.nextbus.com/service/publicXMLFeed?command=messages&a=<agency tag>&r=<route tag1>&r=<route tagN>
Obtain messages currently active for a route or a group of routes. Note: this command only returns currently active messages. If a message is configured just to be shown on Tuesdays for example but it is currently Wednesday then the message will not be listed.
http://webservices.nextbus.com/service/publicXMLFeed?command=vehicleLocations&a=<agency_tag>&r=<route tag>&t=<epoch time in msec>
Obtain a list of vehicle locations that have changed since the last time the vehicleLocations command was used. The "t" parameter specifies the last time that was returned by the vehicleLocations command. The time is in msec since the 1970 epoch time. If you specify a time of 0, then data for the last 15 minutes is provided.
I have a problem where not all stops returns are in directions, so I don't know which direction the stop is on.