Split network into segments and report distance

back/data/network.js

@@ -12,7 +12,8 @@
  * the `script/update-network` script.
  */
 
-const {choosePlural, joinSentence} = require('../util');
+const geolib = require('geolib');
+const util = require('../util');
 const osm = require('./sources/osm');
 const tam = require('./sources/tam');
 
@@ -163,6 +164,9 @@ out body qt;
     // All transport lines of the network
     const lines = {};
 
+    // All segments leading from one stop to another
+    const segments = {};
+
     for (let routeMaster of routeMasters)
     {
         const lineRef = routeMaster.tags.ref;
@@ -236,9 +240,9 @@ URI: ${osm.viewNode(stop.id)}
                             {
                                 console.warn(`\
     — Stop ${candidate.stopRef} with name “${candidate.name}” used by \
-${choosePlural(candidate.lines.length, 'line', '.s')} \
-${joinSentence(Array.from(candidate.lines), ', ', ' and ')} going to \
-${joinSentence(Array.from(candidate.directions), ', ', ' or ')}
+${util.choosePlural(candidate.lines.length, 'line', '.s')} \
+${util.joinSentence(Array.from(candidate.lines), ', ', ' and ')} going to \
+${util.joinSentence(Array.from(candidate.directions), ', ', ' or ')}
       Apply in JOSM: ${osm.addTagsToNode(stop.id, ['ref=' + candidate.stopRef])}
 `);
                             }
@@ -368,22 +372,65 @@ ${name} is one-way and cannot be used in reverse.`);
             }
 
             // Split the path into segments between stops
-            const segments = [];
-
             for (let stopIndex = 0; stopIndex + 1 < stops.length; ++stopIndex)
             {
-                segments.push(path.slice(
+                const begin = elements[stops[stopIndex]].tags.ref;
+                const end = elements[stops[stopIndex + 1]].tags.ref;
+
+                const id = `${begin}-${end}`;
+                const nodes = path.slice(
                     path.indexOf(stops[stopIndex]),
                     path.indexOf(stops[stopIndex + 1]) + 1,
-                ).map(id => ({
-                    lat: elements[id].lat,
-                    lon: elements[id].lon
-                })));
+                );
+
+                if (id in segments)
+                {
+                    if (!util.arraysEqual(nodes, segments[id].nodes))
+                    {
+                        throw new Error(`Segment ${id} is defined as a
+different sequence of nodes in two or more lines.`);
+                    }
+
+                    segments[id].lines.add(lineRef);
+                }
+                else
+                {
+                    const points = nodes.map(id => ({
+                        lat: elements[id].lat,
+                        lon: elements[id].lon
+                    }));
+
+                    if (points.length)
+                    {
+                        // Augment each point with the distance to the start
+                        points[0].distance = 0;
+
+                        for (let i = 1; i < points.length; ++i)
+                        {
+                            const len = geolib.getPreciseDistance(
+                                ...[points[i - 1], points[i]]
+                                    .map(({lat, lon}) => ({
+                                        latitude: lat,
+                                        longitude: lon
+                                    })),
+                            );
+
+                            points[i].distance = points[i - 1].distance + len;
+                        }
+                    }
+
+                    segments[id] = {
+                        // Keep track of the original sequence of nodes to
+                        // compare with duplicates
+                        nodes,
+                        points,
+                        lines: new Set([lineRef]),
+                    };
+                }
             }
 
             routes.push({
                 from, to, name,
-                segments,
                 stops: stops.map(id => elements[id].tags.ref),
             });
         }
@@ -394,7 +441,13 @@ ${name} is one-way and cannot be used in reverse.`);
         };
     }
 
-    return {stops, lines};
+    // Remove OSM nodes from segments that were only used for checking validity
+    for (let segment of Object.values(segments))
+    {
+        delete segment.nodes;
+    }
+
+    return {stops, lines, segments};
 };
 
 exports.fetch = fetch;

back/data/sources/osm.js

@@ -22,8 +22,10 @@ const {isObject} = require('../../util');
 const runQuery = (
     query,
     endpoint = 'https://lz4.overpass-api.de/api/interpreter'
-) => axios.post(endpoint, 'data=' + query)
-    .then(res => res.data);
+) => (
+    axios.post(endpoint, 'data=' + query)
+    .then(res => res.data)
+);
 
 exports.runQuery = runQuery;
 
@@ -37,12 +39,13 @@ exports.runQuery = runQuery;
  * @param tags List of tags to add, in the `key=value` format.
  * @return Link for remotely adding the tags.
  */
-const addTagsToNode = (id, tags) =>
+const addTagsToNode = (id, tags) => (
     'http://127.0.0.1:8111/load_object?' + [
         `objects=n${id}`,
         'new_layer=false',
         'addtags=' + tags.join('%7C'),
-    ].join('&');
+    ].join('&')
+);
 
 exports.addTagsToNode = addTagsToNode;
 
@@ -64,11 +67,12 @@ exports.viewNode = viewNode;
  * @param tags Set of tags of the way.
  * @return True iff. the way is one-way.
  */
-const isOneWay = object =>
+const isOneWay = object => (
     object.type === 'way'
     && isObject(object.tags)
     && (object.tags.oneway === 'yes' || object.tags.junction === 'roundabout'
-        || object.tags.highway === 'motorway');
+        || object.tags.highway === 'motorway')
+);
 
 exports.isOneWay = isOneWay;
 
@@ -81,9 +85,10 @@ exports.isOneWay = isOneWay;
  * @param object OSM object.
  * @return True iff. the relation is a public transport line.
  */
-const isTransportLine = object =>
+const isTransportLine = object => (
     object.type === 'relation'
     && isObject(object.tags)
-    && object.tags.type === 'route_master';
+    && object.tags.type === 'route_master'
+);
 
 exports.isTransportLine = isTransportLine;

back/util.js

@@ -52,9 +52,11 @@ const joinSentence = (array, separator, lastSeparator) =>
         return array.join(lastSeparator);
     }
 
-    return array.slice(0, -1).join(separator)
-        + lastSeparator
-        + array[array.length - 1];
+    return (
+        array.slice(0, -1).join(separator)
+            + lastSeparator
+            + array[array.length - 1]
+    );
 };
 
 exports.joinSentence = joinSentence;
@@ -68,3 +70,17 @@ exports.joinSentence = joinSentence;
 const isObject = value => value !== null && typeof value === 'object';
 
 exports.isObject = isObject;
+
+/**
+ * Check if two arrays are equal in a shallow manner.
+ *
+ * @param array1 First array.
+ * @param array2 Second array.
+ * @return True iff. the two arrays are equal.
+ */
+const arraysEqual = (array1, array2) => (
+    array1.length === array2.length
+    && array1.every((elt1, index) => elt1 === array2[index])
+);
+
+exports.arraysEqual = arraysEqual;

front/map.js

@@ -29,23 +29,21 @@ const makeDataSources = async () =>
     const stopsSource = new VectorSource();
 
     segmentsSource.addFeatures(
-        Object.values(network.lines).flatMap(({color, routes}) =>
-            routes.map(({segments}) =>
-                new Feature({
-                    color,
-                    geometry: new LineString(segments.flat().map(
-                        ({lat, lon}) => proj.fromLonLat([lon, lat])
-                    )),
-                })
-            )
+        Object.values(network.segments).map(({lines, points}) =>
+            new Feature({
+                colors: lines.map(line => network.lines[line].color),
+                geometry: new LineString(points.map(
+                    ({lat, lon}) => proj.fromLonLat([lon, lat])
+                )),
+            })
         )
     );
 
     stopsSource.addFeatures(
-        Object.entries(network.stops).map(([stopId, stop]) =>
+        Object.values(network.stops).map(({lines, lon, lat}) =>
             new Feature({
-                color: network.lines[stop.lines[0]].color,
-                geometry: new Point(proj.fromLonLat([stop.lon, stop.lat])),
+                colors: lines.map(line => network.lines[line].color),
+                geometry: new Point(proj.fromLonLat([lon, lat])),
             })
         )
     );
@@ -62,14 +60,14 @@ const makeBorderColor = mainColor =>
 
 const segmentsBorderStyle = feature => new Style({
     stroke: new Stroke({
-        color: makeBorderColor(feature.get('color')),
+        color: makeBorderColor(feature.get('colors')[0]),
         width: 8,
     }),
 });
 
 const segmentsInnerStyle = feature => new Style({
     stroke: new Stroke({
-        color: feature.get('color'),
+        color: feature.get('colors')[0],
         width: 6,
     }),
 });
@@ -77,10 +75,10 @@ const segmentsInnerStyle = feature => new Style({
 const stopsStyle = feature => new Style({
     image: new Circle({
         fill: new Fill({
-            color: feature.get('color'),
+            color: feature.get('colors')[0],
         }),
         stroke: new Stroke({
-            color: makeBorderColor(feature.get('color')),
+            color: makeBorderColor(feature.get('colors')[0]),
             width: 1.5,
         }),
         radius: 6,