src/main/java/com/conveyal/gtfs/GTFSFeed.java
public STRtree getSpatialIndex () {
        if (this.spatialIndex == null) {
            synchronized (this) {
                if (this.spatialIndex == null) {
                    // build spatial index
                    STRtree stopIndex = new STRtree();
                    for(Stop stop : this.stops.values()) {
                        try {
                            if (Double.isNaN(stop.stop_lat) || Double.isNaN(stop.stop_lon)) {
                                continue;
                            }
                            Coordinate stopCoord = new Coordinate(stop.stop_lat, stop.stop_lon);
                            stopIndex.insert(new Envelope(stopCoord), stop);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }

                    }
                    try {
                        stopIndex.build();
                        this.spatialIndex = stopIndex;
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
        return this.spatialIndex;
    }
public STRtree getSpatialIndex () {
        if (this.spatialIndex == null) {
            synchronized (this) {
                if (this.spatialIndex == null) {
                    // build spatial index
                    STRtree stopIndex = new STRtree();
                    for(Stop stop : this.stops.values()) {
                        try {
                            if (Double.isNaN(stop.stop_lat) || Double.isNaN(stop.stop_lon)) {
                                continue;
                            }
                            Coordinate stopCoord = new Coordinate(stop.stop_lat, stop.stop_lon);
                            stopIndex.insert(new Envelope(stopCoord), stop);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }

                    }
                    try {
                        stopIndex.build();
                        this.spatialIndex = stopIndex;
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }
        }
        return this.spatialIndex;
    }
TODO rename getStopSpatialIndex to make it clear what the index contains.