accept GTFS with pathway stop location_types

This is the first step of #803.
It will gracefully ignore pathway nodes and reduce errors, but does not
yet build the routable edges inside the stations.

src/main/java/com/conveyal/analysis/controllers/GtfsController.java

@@ -151,7 +151,8 @@ static class StopApiResponse extends BaseApiResponse {
         }
     }
     /**
-     * Return StopApiResponse values for GTFS stops (location_type = 0) in a single feed
+     * Return StopApiResponse values for GTFS stops (location_type = 0) in a single feed.
+     * All other location_types (station, entrance, generic node, boarding area) are skipped.
      */
     private List<StopApiResponse> getAllStopsForOneFeed(Request req, Response res) {
         GTFSFeed feed = getFeedFromRequest(req);
@@ -160,8 +161,8 @@ private List<StopApiResponse> getAllStopsForOneFeed(Request req, Response res) {
     }
 
     /**
-     * Groups the feedId and stops (location_type = 0; not parent stations, entrances/exits, generic nodes, etc.) for a
-     * given GTFS feed
+     * Compound return type for the feedId and stops with location_type = 0 for a given GTFS feed.
+     * All other location_types (station, entrance, generic node, boarding area) are skipped.
      */
     static class FeedGroupStopsApiResponse {
         public final String feedId;

src/main/java/com/conveyal/gtfs/GTFSCache.java

@@ -220,6 +220,12 @@ private void buildStopsIndex (String bundleScopedFeedId, STRtree tree) {
         final GTFSFeed feed = this.get(bundleScopedFeedId);
         LOG.info("{}: indexing {} stops", feed.feedId, feed.stops.size());
         for (Stop stop : feed.stops.values()) {
+            // To match existing GTFS API, include only stop objects that have location_type 0.
+            // All other location_types (station, entrance, generic node, boarding area) are skipped.
+            // Missing (NaN) coordinates will confuse the spatial index and cascade hundreds of errors.
+            if (stop.location_type != 0 || !Double.isFinite(stop.stop_lat) || !Double.isFinite(stop.stop_lon)) {
+                continue;
+            }
             Envelope stopEnvelope = new Envelope(stop.stop_lon, stop.stop_lon, stop.stop_lat, stop.stop_lat);
             Point point = GeometryUtils.geometryFactory.createPoint(new Coordinate(stop.stop_lon, stop.stop_lat));
 

src/main/java/com/conveyal/gtfs/model/Calendar.java

@@ -41,7 +41,8 @@ public Loader(GTFSFeed feed, Map<String, Service> services) {
 
         @Override
         protected boolean isRequired() {
-            return true;
+            // One of calendar or calendar_dates must be present - check in more flexible modular validation later.
+            return false;
         }
 
         @Override

src/main/java/com/conveyal/gtfs/model/CalendarDate.java

@@ -41,6 +41,7 @@ public Loader(GTFSFeed feed, Map<String, Service> services) {
 
         @Override
         protected boolean isRequired() {
+            // One of calendar or calendar_dates must be present - check in more flexible modular validation later.
             return false;
         }
 

src/main/java/com/conveyal/gtfs/model/Entity.java

@@ -208,6 +208,7 @@ protected URL getUrlField(String column, boolean required) throws IOException {
             return url;
         }
 
+        /** @return NaN if the number is missing or cannot be parsed. */
         protected double getDoubleField(String column, boolean required, double min, double max) throws IOException {
             String str = getFieldCheckRequired(column, required);
             double val = Double.NaN;

src/main/java/com/conveyal/gtfs/model/Stop.java

@@ -48,17 +48,20 @@ public void loadOneRow() throws IOException {
             s.stop_code = getStringField("stop_code", false);
             s.stop_name = getStringField("stop_name", true);
             s.stop_desc = getStringField("stop_desc", false);
-            s.stop_lat  = getDoubleField("stop_lat", true, -90D, 90D);
-            s.stop_lon  = getDoubleField("stop_lon", true, -180D, 180D);
             s.zone_id   = getStringField("zone_id", false);
             s.stop_url  = getUrlField("stop_url", false);
-            s.location_type  = getIntField("location_type", false, 0, 1);
-            s.parent_station = getStringField("parent_station", false);
-            s.stop_timezone  = getStringField("stop_timezone", false);
+            s.location_type  = getIntField("location_type", false, 0, 4);
+            // 0...2 are stop, station, and entrance which must have lat and lon. Other nodes do not need coordinates.
+            boolean coord_required = s.location_type > 2;
+            s.stop_lat  = getDoubleField("stop_lat", coord_required, -90D, 90D);
+            s.stop_lon  = getDoubleField("stop_lon", coord_required, -180D, 180D);
+            // Required for entrances, generic nodes, and boarding areas. Optional for stops, forbidden for stations.
+            boolean parent_station_required = s.location_type >= 2;
+            s.parent_station = getStringField("parent_station", parent_station_required);
+            s.stop_timezone  = getStringField("stop_timezone", parent_station_required);
             s.wheelchair_boarding = getStringField("wheelchair_boarding", false);
             s.feed_id = feed.feedId;
             /* TODO check ref integrity later, this table self-references via parent_station */
-
             feed.stops.put(s.stop_id, s);
         }