wow it work

nate-parrott · Dec 7, 2017 · f75e14a · f75e14a
1 parent 63c960a
commit f75e14a
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Showing 6 changed files with 144 additions and 9 deletions.
diff --git a/gtfs_json.js b/gtfs_json.js
diff --git a/gtfs_json.py b/gtfs_json.py
@@ -0,0 +1,63 @@
+import json
+import csv
+from collections import defaultdict
+import os
+
+HOURS = 60 * 60
+
+def gtfs_json(gtfs_path, included_service_groups=[], min_time=0, max_time=48*HOURS):
+    def read_csv(name):
+        return list(csv.DictReader(open(os.path.join(gtfs_path, name + '.txt'))))
+
+    parent_stops = {}
+    for stop in read_csv('stops'):
+        if stop['parent_station']:
+            parent_stops[stop['stop_id']] = stop['parent_station']
+    def resolve_stop_id(stop_id):
+        return parent_stops.get(stop_id, stop_id)
+
+    transfers = defaultdict(list)
+    for transfer in read_csv('transfers'):
+        if transfer['transfer_type'] != '3': # 3 is 'no transfers'
+            from_stop_id = resolve_stop_id(transfer['from_stop_id'])
+            to_stop_id = resolve_stop_id(transfer['to_stop_id'])
+            transfers[from_stop_id].append({"to": to_stop_id, "time": float(transfer['min_transfer_time'] or "0")})
+
+    routes_by_id = {route['route_id']: route for route in read_csv('routes')}
+    trips_by_id = {trip['trip_id']: trip for trip in read_csv('trips')}
+    stop_times = read_csv('stop_times')
+
+    service_groups = {
+        'saturday': ['A20171105SAT', 'B20171105SAT'],
+        'sunday': ['A20171105SUN', 'B20171105SUN'],
+        'weekdays': ['A20171105WKD', 'B20171105WKD']
+    }
+
+    events_by_service_group = {}
+    for service_group, service_ids in service_groups.items():
+        if service_group in included_service_groups:
+            events = []
+            for stop_time in stop_times:
+                trip = trips_by_id[stop_time['trip_id']]
+                route = routes_by_id[trip['route_id']]
+                if trip['service_id'] in service_ids:
+                    time = time_str_to_float(stop_time['departure_time'])
+                    if time >= min_time and time <= max_time:
+                        stop_id = resolve_stop_id(stop_time['stop_id'])
+                        events.append({"time": time, "trip_id": stop_time['trip_id'], "stop_id": stop_id, "route_name": route['route_short_name']})
+            events.sort(key=lambda x: x['time'])
+            events_by_service_group[service_group] = events
+    return {
+        "transfers": transfers,
+        "events_by_service_group": events_by_service_group
+    }
+
+def time_str_to_float(t): # in seconds
+    parts = t.split(':')
+    hours, mins, secs = map(float, parts)
+    return hours * 60 * 60 + mins * 60 + secs
+assert time_str_to_float('01:23:00') == 1 * 60 * 60 + 23 * 60
+
+if __name__ == '__main__':
+    j = gtfs_json('google_transit', ['weekdays'], 8*HOURS, 11*HOURS)
+    open('gtfs_json.js', 'w').write('gtfs_json = ' + json.dumps(j))
diff --git a/index.html b/index.html
@@ -14,9 +14,9 @@
     }
   </style>
   <script src="subway.js"></script>
-  <script src="routing_graph.js"></script>
+  <script src="gtfs_json.js"></script>
   <script src="https://unpkg.com/js-heap@0.3.1/heap.js"></script>
-  <script src="routing.js"></script>
+  <script src="virtual_rider.js"></script>
 </head>
 <body>
   <script>
@@ -29,7 +29,7 @@
 		let computeStationPositions = (originStationId) => {
 			let originLat = stations[originStationId].lat;
 			let originLon = stations[originStationId].lon;
-			let travelTimes = travelTimesToAllStations(originStationId);
+			let travelTimes = computeTravelTimes(originStationId, Object.keys(stations), gtfs_json, 8 * 60 * 60, 'weekdays');
 
 			let maxTravelTime = 70 * 60;
 
@@ -39,18 +39,19 @@
 
 				let deltaY = lat - originLat;
 				let deltaX = (lon - originLon) * 0.767;
-				let angle = Math.atan2(deltaY, deltaX);
+				let angle = Math.atan2(deltaY, deltaX) + 30 / 180 * Math.PI;
 				let origDist = Math.sqrt(Math.pow(deltaX, 2) + Math.pow(deltaY, 2));
 
-				let dist = (travelTimes[stationId] || maxTravelTime) / maxTravelTime;
+				let dist = (travelTimes[stationId]) / maxTravelTime;
 				positions[stationId] = {x: Math.cos(angle) * dist, y: Math.sin(angle) * dist};
 			}
 
 			return positions;
 		}
 
-		let stationPositions = computeStationPositions('127'); // times sq
-		console.log(stationPositions);
+		let homeStationId = 'R32';
+		let stationPositions = computeStationPositions(homeStationId); // times sq
+		// console.log(stationPositions);
 
     let xValue = (stationId) => stationPositions[stationId].x;
     let yValue = (stationId) => stationPositions[stationId].y;
@@ -66,6 +67,7 @@
     // let stationList = Object.values(lines)[0].stations;
     // svg.selectAll('.stop').data(stationList).enter().append('circle').attr('class', 'stop').attr('r', 3.5).attr('cx', xMap).attr('cy', yMap).style('fill', 'black');
     svg.selectAll('.stop').data(Object.keys(stations)).enter().append('circle').attr('class', 'stop').attr('r', '1.5').attr('fill', 'black').attr('cx', xMap).attr('cy', yMap);
+		svg.selectAll('home').data([homeStationId]).enter().append('circle').attr('class', 'home').attr('r', '3').attr('fill', 'white').attr('stroke', 'black').attr('stroke-width', 2).attr('cx', xMap).attr('cy', yMap);
 
   </script>
 </body>

diff --git a/subway.js b/subway.js
diff --git a/subway.json b/subway.json
diff --git a/virtual_rider.js b/virtual_rider.js
@@ -0,0 +1,69 @@
+
+let atStopState = (id) => "at_stop:" + id;
+let onTripState = (id) => "on_trip:" + id;
+
+class StateMap {
+	constructor() {
+		this.earliestRidersAtStates = {};
+	}
+	addRider(rider) {
+		let existing = this.earliestRidersAtStates[rider.state];
+		if (!existing || rider.time < existing.time) {
+			this.earliestRidersAtStates[rider.state] = rider;
+			return true;
+		}
+		return false;
+	}
+	addRiderAndTransfersByAppendingStop(oldRider, stopId, time, allTransfers) {
+		let direct = oldRider.byAdding(atStopState(stopId), time);
+		if (this.addRider(direct)) {
+			// add all transfers:
+			for (let transfer of allTransfers[stopId] || []) {
+				this.addRiderAndTransfersByAppendingStop(direct, transfer['to'], time + transfer.time, allTransfers);
+			}
+		}
+	}
+}
+
+class Rider {
+	constructor(states, time) {
+		this.states = states; // parts are strings
+		this.time = time;
+		this.state = states.length ? states[states.length-1] : null;
+	}
+	byAdding(state, finalTime) {
+		return new Rider([...this.states, state], finalTime);
+	}
+}
+
+let computeTravelTimes = (startStationId, endStationIds, gtfs_json, startTime, serviceGroup) => {
+	let stateMap = new StateMap();
+
+	let emptyPath = new Rider([], startTime);
+	stateMap.addRiderAndTransfersByAppendingStop(emptyPath, startStationId, startTime, gtfs_json.transfers);
+	// console.log(stateMap);
+
+	for (let {time, trip_id, stop_id, route_name} of gtfs_json.events_by_service_group[serviceGroup]) {
+		// model exiting the train:
+		let riderOnTrain = stateMap.earliestRidersAtStates[onTripState(trip_id)];
+		if (riderOnTrain && riderOnTrain.time <= time) {
+			stateMap.addRiderAndTransfersByAppendingStop(riderOnTrain, stop_id, time, gtfs_json.transfers);
+		}
+		// model boarding the train:
+		let riderOnPlatform = stateMap.earliestRidersAtStates[atStopState(stop_id)];
+		if (riderOnPlatform && riderOnPlatform.time <= time) {
+			let riderOnTrain = riderOnPlatform.byAdding(onTripState(trip_id), time);
+			stateMap.addRider(riderOnTrain);
+		}
+	}
+
+	let travelTimes = {};
+	for (let stationId of endStationIds) {
+		let rider = stateMap.earliestRidersAtStates[atStopState(stationId)];
+		travelTimes[stationId] = rider ? rider.time - startTime : null;
+	}
+	return travelTimes;
+}
+
+// let HOURS = 60 * 60;
+// console.log(computeTravelTimes('127', Object.keys(subway.stations), 8*HOURS, gtfs_json, 'weekdays'));