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Merge pull request #399 from conveyal/add-stoptime-interpolation
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Add Stop Time Interpolation
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@philip-cline
philip-cline committed Nov 21, 2023
2 parents 9bc752d + a331d74 commit b657dfe
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Showing 3 changed files with 166 additions and 36 deletions.
77 changes: 70 additions & 7 deletions src/main/java/com/conveyal/gtfs/loader/JdbcTableWriter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -257,13 +257,21 @@ public String update(Integer id, String json, boolean autoCommit) throws SQLExce
}
}

/**
* Deprecated method to normalize stop times before stop time interpolation. Defaults to
* false for interpolation.
*/
public int normalizeStopTimesForPattern(int id, int beginWithSequence) throws SQLException {
return normalizeStopTimesForPattern(id, beginWithSequence, false);
}

/**
* For a given pattern id and starting stop sequence (inclusive), normalize all stop times to match the pattern
* stops' travel times.
*
* @return number of stop times updated
*/
public int normalizeStopTimesForPattern(int id, int beginWithSequence) throws SQLException {
public int normalizeStopTimesForPattern(int id, int beginWithSequence, boolean interpolateStopTimes) throws SQLException {
try {
JDBCTableReader<PatternStop> patternStops = new JDBCTableReader(
Table.PATTERN_STOP,
Expand All @@ -280,7 +288,7 @@ public int normalizeStopTimesForPattern(int id, int beginWithSequence) throws SQ
patternStopsToNormalize.add(patternStop);
}
}
int stopTimesUpdated = updateStopTimesForPatternStops(patternStopsToNormalize);
int stopTimesUpdated = updateStopTimesForPatternStops(patternStopsToNormalize, interpolateStopTimes);
connection.commit();
return stopTimesUpdated;
} catch (Exception e) {
Expand Down Expand Up @@ -771,6 +779,36 @@ private int updateStopTimesForPatternStop(ObjectNode patternStop, int previousTr
return travelTime + dwellTime;
}

/**
* Updates the non-timepoint stop times between two timepoints using the speed implied by
* the travel time between them. Ignores any existing default_travel_time or default_dwell_time
* entered for the non-timepoint stops.
*/
private int interpolateTimesFromTimepoints(
PatternStop patternStop,
List<PatternStop> timepoints,
Integer timepointNumber,
double previousShapeDistTraveled
) {
if (timepointNumber == 0 || timepoints.size() == 1 || timepointNumber >= timepoints.size()) {
throw new IllegalStateException("Issue in pattern stops which prevents interpolation (e.g. less than 2 timepoints)");
}
PatternStop nextTimepoint = timepoints.get(timepointNumber);
PatternStop lastTimepoint = timepoints.get(timepointNumber-1);

if (
nextTimepoint == null ||
nextTimepoint.default_travel_time == Entity.INT_MISSING ||
nextTimepoint.shape_dist_traveled == Entity.DOUBLE_MISSING ||
lastTimepoint.shape_dist_traveled == Entity.DOUBLE_MISSING
) {
throw new IllegalStateException("Error with stop time interpolation: timepoint or shape_dist_traveled is null");
}

double timepointSpeed = (nextTimepoint.shape_dist_traveled - lastTimepoint.shape_dist_traveled) / nextTimepoint.default_travel_time;
return (int) Math.round((patternStop.shape_dist_traveled - previousShapeDistTraveled) / timepointSpeed);
}

/**
* Normalizes all stop times' arrivals and departures for an ordered set of pattern stops. This set can be the full
* set of stops for a pattern or just a subset. Typical usage for this method would be to overwrite the arrival and
Expand All @@ -781,8 +819,9 @@ private int updateStopTimesForPatternStop(ObjectNode patternStop, int previousTr
*
* TODO? add param Set<String> serviceIdFilters service_id values to filter trips on
*/
private int updateStopTimesForPatternStops(List<PatternStop> patternStops) throws SQLException {
private int updateStopTimesForPatternStops(List<PatternStop> patternStops, boolean interpolateStopTimes) throws SQLException {
PatternStop firstPatternStop = patternStops.iterator().next();
List<PatternStop> timepoints = patternStops.stream().filter(ps -> ps.timepoint == 1).collect(Collectors.toList());
int firstStopSequence = firstPatternStop.stop_sequence;
// Prepare SQL query to determine the time that should form the basis for adding the travel time values.
int previousStopSequence = firstStopSequence > 0 ? firstStopSequence - 1 : 0;
Expand Down Expand Up @@ -815,16 +854,40 @@ private int updateStopTimesForPatternStops(List<PatternStop> patternStops) throw
for (String tripId : timesForTripIds.keySet()) {
// Initialize travel time with previous stop time value.
int cumulativeTravelTime = timesForTripIds.get(tripId);
int cumulativeInterpolatedTime = cumulativeTravelTime;
int timepointNumber = 0;
double previousShapeDistTraveled = 0; // Used for calculating timepoint speed for interpolation
for (PatternStop patternStop : patternStops) {
boolean isTimepoint = patternStop.timepoint == 1;
if (isTimepoint) timepointNumber++;
// Gather travel/dwell time for pattern stop (being sure to check for missing values).
int travelTime = patternStop.default_travel_time == Entity.INT_MISSING ? 0 : patternStop.default_travel_time;
if (interpolateStopTimes) {
if (patternStop.shape_dist_traveled == Entity.DOUBLE_MISSING) {
throw new IllegalStateException("Shape_dist_traveled must be defined for all stops in order to perform interpolation");
}
// Override travel time if we're interpolating between timepoints.
if (!isTimepoint) travelTime = interpolateTimesFromTimepoints(patternStop, timepoints, timepointNumber, previousShapeDistTraveled);
previousShapeDistTraveled += patternStop.shape_dist_traveled;
}
int dwellTime = patternStop.default_dwell_time == Entity.INT_MISSING ? 0 : patternStop.default_dwell_time;
int oneBasedIndex = 1;
// Increase travel time by current pattern stop's travel and dwell times (and set values for update).
cumulativeTravelTime += travelTime;
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeTravelTime);
cumulativeTravelTime += dwellTime;
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeTravelTime);
if (!isTimepoint && interpolateStopTimes) {
// We don't want to increment the true cumulative travel time because that adjusts the timepoint
// times later in the pattern.
// Dwell times are ignored right now as they do not fit the typical use case for interpolation.
// They may be incorporated by accounting for all dwell times in intermediate stops when calculating
// the timepoint speed.
cumulativeInterpolatedTime += travelTime;
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeInterpolatedTime);
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeInterpolatedTime);
} else {
cumulativeTravelTime += travelTime;
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeTravelTime);
cumulativeTravelTime += dwellTime;
updateStopTimeStatement.setInt(oneBasedIndex++, cumulativeTravelTime);
}
updateStopTimeStatement.setString(oneBasedIndex++, tripId);
updateStopTimeStatement.setInt(oneBasedIndex++, patternStop.stop_sequence);
stopTimesTracker.addBatch();
Expand Down
8 changes: 8 additions & 0 deletions src/test/java/com/conveyal/gtfs/dto/PatternStopDTO.java
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Original file line number Diff line number Diff line change
Expand Up @@ -23,4 +23,12 @@ public PatternStopDTO (String patternId, String stopId, int stopSequence) {
stop_id = stopId;
stop_sequence = stopSequence;
}

public PatternStopDTO (String patternId, String stopId, int stopSequence, int timepointValue, double shape_dist_traveledValue) {
timepoint = timepointValue;
pattern_id = patternId;
stop_id = stopId;
stop_sequence = stopSequence;
shape_dist_traveled = shape_dist_traveledValue;
}
}
117 changes: 88 additions & 29 deletions src/test/java/com/conveyal/gtfs/loader/JDBCTableWriterTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -64,9 +64,12 @@ public class JDBCTableWriterTest {
private static String testGtfsGLSnapshotNamespace;
private static String simpleServiceId = "1";
private static String firstStopId = "1";
private static String secondStopId= "1.5";
private static String lastStopId = "2";
private static double firstStopLat = 34.2222;
private static double firstStopLon = -87.333;
private static double secondStopLat = 34.2227;
private static double secondStopLon = -87.3335;
private static double lastStopLat = 34.2233;
private static double lastStopLon = -87.334;
private static String sharedShapeId = "shared_shape_id";
Expand All @@ -93,6 +96,7 @@ public static void setUpClass() throws SQLException, IOException, InvalidNamespa
// Create a service calendar and two stops, both of which are necessary to perform pattern and trip tests.
createWeekdayCalendar(simpleServiceId, "20180103", "20180104");
createSimpleStop(firstStopId, "First Stop", firstStopLat, firstStopLon);
createSimpleStop(secondStopId, "Second Stop", secondStopLat, secondStopLon);
createSimpleStop(lastStopId, "Last Stop", lastStopLat, lastStopLon);

/** Load the following real-life GTFS for use with {@link JDBCTableWriterTest#canUpdateServiceId()} **/
Expand Down Expand Up @@ -838,29 +842,25 @@ public void canCreateUpdateAndDeleteFrequencyTripForFrequencyPattern() throws IO
));
}

/**
* Checks that {@link JdbcTableWriter#normalizeStopTimesForPattern(int, int)} can normalize stop times to a pattern's
* default travel times.
*/
@Test
public void canNormalizePatternStopTimes() throws IOException, SQLException, InvalidNamespaceException {
// Store Table and Class values for use in test.
private static String normalizeStopsForPattern(
PatternStopDTO[] patternStops,
int updatedStopSequence,
boolean interpolateStopTimes,
int initialTravelTime,
int updatedTravelTime,
int startTime,
String patternId
) throws SQLException, InvalidNamespaceException, IOException {
final Table tripsTable = Table.TRIPS;
int initialTravelTime = 60; // one minute
int startTime = 6 * 60 * 60; // 6AM
String patternId = "123456";
PatternStopDTO[] patternStops = new PatternStopDTO[]{
new PatternStopDTO(patternId, firstStopId, 0),
new PatternStopDTO(patternId, lastStopId, 1)
};
patternStops[1].default_travel_time = initialTravelTime;

PatternDTO pattern = createRouteAndPattern(newUUID(),
patternId,
"Pattern A",
null,
new ShapePointDTO[]{},
patternStops,
0);
patternId,
"Pattern A",
null,
new ShapePointDTO[]{},
patternStops,
0);

// Create trip with travel times that match pattern stops.
TripDTO tripInput = constructTimetableTrip(pattern.pattern_id, pattern.route_id, startTime, initialTravelTime);
JdbcTableWriter createTripWriter = createTestTableWriter(tripsTable);
Expand All @@ -869,20 +869,79 @@ public void canNormalizePatternStopTimes() throws IOException, SQLException, Inv
TripDTO createdTrip = mapper.readValue(createTripOutput, TripDTO.class);
// Update pattern stop with new travel time.
JdbcTableWriter patternUpdater = createTestTableWriter(Table.PATTERNS);
int updatedTravelTime = 3600; // one hour
pattern.pattern_stops[1].default_travel_time = updatedTravelTime;
pattern.pattern_stops[updatedStopSequence].default_travel_time = updatedTravelTime;
String updatedPatternOutput = patternUpdater.update(pattern.id, mapper.writeValueAsString(pattern), true);
LOG.info("Updated pattern output: {}", updatedPatternOutput);
// Normalize stop times.
JdbcTableWriter updateTripWriter = createTestTableWriter(tripsTable);
updateTripWriter.normalizeStopTimesForPattern(pattern.id, 0);
updateTripWriter.normalizeStopTimesForPattern(pattern.id, 0, interpolateStopTimes);

return createdTrip.trip_id;
}

/**
* Checks that {@link JdbcTableWriter#normalizeStopTimesForPattern(int, int, boolean)} can interpolate stop times between timepoints.
*/
@Test
private void canInterpolatePatternStopTimes() throws IOException, SQLException, InvalidNamespaceException {
// Parameters are shared with canNormalizePatternStopTimes, but maintained for test flexibility.
int startTime = 6 * 60 * 60; // 6AM
int initialTravelTime = 60; // seconds
int updatedTravelTime = 600; // ten minutes
String patternId = "123456-interpolated";
double[] shapeDistTraveledValues = new double[] {0.0, 300.0, 600.0};
double timepointTravelTime = (shapeDistTraveledValues[2] - shapeDistTraveledValues[0]) / updatedTravelTime; // 1 m/s

// Create the array of patterns, set the timepoints properly.
PatternStopDTO[] patternStops = new PatternStopDTO[]{
new PatternStopDTO(patternId, firstStopId, 0, 1, shapeDistTraveledValues[0]),
new PatternStopDTO(patternId, secondStopId, 1, 0, shapeDistTraveledValues[1]),
new PatternStopDTO(patternId, lastStopId, 2, 1, shapeDistTraveledValues[2]),
};

patternStops[2].default_travel_time = initialTravelTime;

// Pass the array of patterns to the body method with param
String createdTripId = normalizeStopsForPattern(patternStops, 2, true, initialTravelTime, updatedTravelTime, startTime, patternId);

// Read pattern stops from database and check that the arrivals/departures have been updated.
JDBCTableReader<StopTime> stopTimesTable = new JDBCTableReader(Table.STOP_TIMES,
testDataSource,
testNamespace + ".",
EntityPopulator.STOP_TIME);
testDataSource,
testNamespace + ".",
EntityPopulator.STOP_TIME);
int index = 0;
for (StopTime stopTime : stopTimesTable.getOrdered(createdTripId)) {
LOG.info("stop times i={} arrival={} departure={}", index, stopTime.arrival_time, stopTime.departure_time);
int calculatedArrivalTime = (int) (startTime + shapeDistTraveledValues[index] * timepointTravelTime);
assertThat(stopTime.arrival_time, equalTo(calculatedArrivalTime));
index++;
}
}

/**
* Checks that {@link JdbcTableWriter#normalizeStopTimesForPattern(int, int, boolean)} can normalize stop times to a pattern's
* default travel times.
*/
@Test
public void canNormalizePatternStopTimes() throws IOException, SQLException, InvalidNamespaceException {
// Parameters are shared with canNormalizePatternStopTimes, but maintained for test flexibility.
int initialTravelTime = 60; // one minute
int startTime = 6 * 60 * 60; // 6AM
int updatedTravelTime = 3600;
String patternId = "123456";

PatternStopDTO[] patternStops = new PatternStopDTO[]{
new PatternStopDTO(patternId, firstStopId, 0),
new PatternStopDTO(patternId, lastStopId, 1)
};

String createdTripId = normalizeStopsForPattern(patternStops, 1, false, initialTravelTime, updatedTravelTime, startTime, patternId);
JDBCTableReader<StopTime> stopTimesTable = new JDBCTableReader(Table.STOP_TIMES,
testDataSource,
testNamespace + ".",
EntityPopulator.STOP_TIME);
int index = 0;
for (StopTime stopTime : stopTimesTable.getOrdered(createdTrip.trip_id)) {
for (StopTime stopTime : stopTimesTable.getOrdered(createdTripId)) {
LOG.info("stop times i={} arrival={} departure={}", index, stopTime.arrival_time, stopTime.departure_time);
assertThat(stopTime.arrival_time, equalTo(startTime + index * updatedTravelTime));
index++;
Expand Down Expand Up @@ -990,7 +1049,7 @@ private TripDTO constructFrequencyTrip(String patternId, String routeId, int sta
/**
* Construct (without writing to the database) a timetable trip.
*/
private TripDTO constructTimetableTrip(String patternId, String routeId, int startTime, int travelTime) {
private static TripDTO constructTimetableTrip(String patternId, String routeId, int startTime, int travelTime) {
TripDTO tripInput = new TripDTO();
tripInput.pattern_id = patternId;
tripInput.route_id = routeId;
Expand Down

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