Routes

These helpers read a calculated route. They find where a new stop fits among the existing ones, a section’s bounds, the stretches each route has to itself, the main roads it takes and how it differs from another route, the lanes to take into a maneuver, and the distance, time and position at any point along it. The examples below share this setup:

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import { calculateRoute } from '@tomtom-org/maps-sdk/services';
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const routes = await calculateRoute({ locations: [[4.9, 52.3], [5.1, 52.5]] });
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const route = routes.features[0];
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const waypoints = [[4.9, 52.3], [5.1, 52.5]];

Inserting waypoints

All four helpers project the stops onto the route line and place each new one by where it falls along the route. Waypoints are any WaypointLike: a [longitude, latitude], a GeoJSON Point or a Point feature such as a place.

• An index of 0 means before the origin, and waypoints.length after the destination.
• If the route has fewer than two coordinates, or there are fewer than two existing waypoints, every index is 0 and the helpers prepend new stops.
• For several stops, use the plural helpers instead of the singular one in a loop. They project each stop once, and the result doesn’t depend on the input order.

withInsertedWaypoint

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import { withInsertedWaypoint } from '@tomtom-org/maps-sdk/core';
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const updated = withInsertedWaypoint(route, waypoints, [4.95, 52.35]);
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// [[4.9, 52.3], [4.95, 52.35], [5.1, 52.5]]
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const updatedRoutes = await calculateRoute({ locations: updated });

withInsertedWaypoints

withInsertedWaypoints inserts every new stop in one pass. Each goes to its slot between existing waypoints. Stops that share a slot follow the order in which they fall along the route. Ties keep their input order. Use it, for example, to merge the places discoverPlaces finds along a route:

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import { withInsertedWaypoints } from '@tomtom-org/maps-sdk/core';
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// Passed in any order; returned in along-route order
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const updated = withInsertedWaypoints(route, waypoints, [[5.05, 52.45], [4.95, 52.35]]);
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// [[4.9, 52.3], [4.95, 52.35], [5.05, 52.45], [5.1, 52.5]]

An empty list of new stops returns a copy of waypoints.

findBestWaypointInsertionIndex

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import { findBestWaypointInsertionIndex } from '@tomtom-org/maps-sdk/core';
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findBestWaypointInsertionIndex(route, waypoints, [4.95, 52.35]); // 1: between origin and destination

findBestWaypointInsertionIndices

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import { findBestWaypointInsertionIndices } from '@tomtom-org/maps-sdk/core';
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findBestWaypointInsertionIndices(route, waypoints, [[5.05, 52.45], [4.95, 52.35]]); // [1, 1]

Several stops can share a slot. withInsertedWaypoints also orders them within it.

getSectionBBox

The bounding box of a route section, or any { startPointIndex, endPointIndex }, from its start, middle and end points:

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import { getSectionBBox } from '@tomtom-org/maps-sdk/core';
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for (const section of route.properties.sections.country ?? []) {
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    const bbox = getSectionBBox(route, section);
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    if (bbox) map.mapLibreMap.fitBounds(bbox, { padding: 40 });
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}

Returns BBox | undefined: undefined when the route has no coordinates, or the section’s indices fall outside them or are reversed. Three points are fast, but a winding section can stray outside their box. For a tighter box, pass the section’s slice of coordinates as a LineString to bboxFromGeoJSON.

getSectionOverlap

The stretch two sections of one route share, whatever their types, such as the tolls you pay in one country:

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import { getSectionOverlap } from '@tomtom-org/maps-sdk/core';
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const { country = [], toll = [] } = route.properties.sections;
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const france = country.find((section) => section.countryCodeISO3 === 'FRA');
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const tollsInFrance = france ? toll.filter((section) => getSectionOverlap(section, france)) : [];

Returns RouteSpan | undefined, the shared { startPointIndex, endPointIndex }: undefined when the sections share no segment, as two sections meeting at one point don’t.

getDistinctSections

The stretches of each route that none of the other routes drives, which is what sets an alternative apart. calculateRoute already puts every one of them in sections.distinct when it returns two or more routes. To compare routes from separate calculations, or to keep only the stretches worth naming, call getDistinctSections. Routes match on a road where they carry the same coordinates along it, as the routes of one response do; routes from separate calculations may not.

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import { formatDistance, getDistinctSections } from '@tomtom-org/maps-sdk/core';
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const alternatives = await calculateRoute({ locations: waypoints, maxAlternatives: 2 });
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getDistinctSections(alternatives, { minLengthInMeters: 1000 }).forEach((sections, index) => {
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    const ownMeters = sections.reduce((total, section) => total + section.lengthInMeters, 0);
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    console.log(`Route ${index}: ${formatDistance(ownMeters)} of its own`);
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});

• Each section runs from the coordinate where its route leaves the others to the one where it rejoins them, and carries its lengthInMeters.
• A segment counts as shared when another route drives it in either direction. A route crossing at a junction doesn’t split a section.
• minLengthInMeters leaves out the stretches too short to mention.
• The routing module doesn’t draw them. To ring them on the map, pass their ids to setSectionFocus. It looks the ids up on the shown routes, so pass sections.distinct rather than a list you recomputed.
• Returns DistinctSectionProps[][]: one array per route, in input order. A route that shares every road with the others gets an empty array, and a single route is distinct end to end.

getImportantRoads

The motorways and main roads a route takes, by road number and street name, which is how a driver tells routes apart. Pass a route’s distinct sections as within to name the roads only that route takes:

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import { getImportantRoads } from '@tomtom-org/maps-sdk/core';
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for (const route of alternatives.features) {
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    const roads = getImportantRoads(route, { within: route.properties.sections.distinct, minLengthInMeters: 2000 });
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    console.log(`via ${roads.map((road) => road.name).filter(Boolean).join(', ')}`);
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}

• It reads the route’s importantRoadStretch sections, which calculateRoute returns unless sectionTypes leaves them out.
• A road is every stretch sharing its first road number, or its street name when it has no number. The routing API can rank the stretches of one motorway apart, and you still get the road once. Stretches with neither group by their index and still come back, with no name, so leave them out of what you print.
• within counts only the parts of each road inside the spans you pass, any { startPointIndex, endPointIndex } (RouteSpan) such as sections. Without it, the whole route counts, which is right for a route calculated alone: it has no sections.distinct, as all of it is its own. minLengthInMeters leaves out the roads the route barely touches.
• Each road’s sections are its stretches within the spans, whole. Pass their ids to setSectionFocus to ring the road on the map.
• Returns ImportantRoad[]: { index, name?, roadNumbers, streetName?, lengthInMeters, sections } per road, in order along the route. index is its importance: the lower, the more important.

getSectionsWithin

A route’s sections of every type within spans of it, such as the ferries, tolls and traffic on the roads only that route takes:

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import { formatDistance, getSectionsWithin } from '@tomtom-org/maps-sdk/core';
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for (const route of alternatives.features) {
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    const own = getSectionsWithin(route, { within: route.properties.sections.distinct, types: ['ferry', 'toll', 'traffic'] });
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    if (own.ferry) console.log(`Route ${route.properties.index} takes a ferry for ${formatDistance(own.ferry.lengthInMeters)}`);
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}

• Without types, it reports every section type the route has within the spans. Without within, the whole route counts.
• A section counts when it shares a segment with a span, as getSectionOverlap finds. It comes back whole, so pass its id to setSectionFocus to ring it.
• Returns SectionsWithin: { sections, shares, lengthInMeters } for each type the route has there. lengthInMeters counts only the parts within the spans, and shares gives each section’s part within them, from 0 to 1. traffic holds the traffic sections: multiply a section’s delayInSeconds by its share to count only the delay within the spans.
• To weigh one route against another, use compareRoutes.

compareRoutes

How a route differs from a reference route: what it takes on, and what it stays clear of. For example, weigh an alternative against the route a user selected:

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import { compareRoutes, formatDistance } from '@tomtom-org/maps-sdk/core';
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const [selected, alternative] = (await calculateRoute({ locations: waypoints, maxAlternatives: 1 })).features;
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// The service can return fewer alternatives than asked for
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if (alternative) {
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    const { adds, avoids } = compareRoutes(alternative, selected, { types: ['ferry', 'toll'] });
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    if (avoids.toll) console.log(`Avoids ${formatDistance(avoids.toll.lengthInMeters)} of tolls`);
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}

To tell why the fastest route goes the way it does, compare it with the route typical traffic would take. A route calculated with costModel: { traffic: 'historical' } still carries the live traffic along it, so the comparison names the jams and closures the live route avoids:

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const [live, usual] = await Promise.all([
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    calculateRoute({ locations: waypoints }),
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    calculateRoute({ locations: waypoints, costModel: { traffic: 'historical' } }),
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]);
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const { avoids } = compareRoutes(live.features[0], usual.features[0], { types: ['traffic'] });
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const closures = (avoids.traffic?.sections ?? []).filter((incident) => incident.categories.includes('road-closed'));

• It compares the two routes alone, rather than reading their sections.distinct, which were found against every route of their response.
• Routes of separate calls compare where they carry the same coordinates along a road they share. Where they don’t, that road counts as distinct on both sides.
• It weighs every section type the routing service returns unless you pass types, leaving out leg and distinct.
• A closed road holds no delay, so name a closure from its categories rather than timing it.
• Returns RouteComparison: { distinct, referenceDistinct, adds, avoids }. distinct and referenceDistinct are the stretches each route drives alone, both empty when the two take the same roads. adds is getSectionsWithin on the route’s stretches, and avoids on the reference’s.
• The route with alternatives example weighs each route against the selected one, or against the usual route.

getInstructionLanes

Finds the lanes section leading to an instruction’s maneuver, so you can show the lanes to take beside each step of a directions list. The routing module doesn’t draw lanes on the map. calculateRoute returns lanes sections only when you request guidance.

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import { getInstructionLanes } from '@tomtom-org/maps-sdk/core';
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const guided = await calculateRoute({ locations: waypoints, guidance: { type: 'coded' } });
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const guidedRoute = guided.features[0];
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for (const instruction of guidedRoute.properties.guidance?.instructions ?? []) {
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    const lanes = getInstructionLanes(guidedRoute, instruction);
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    // lanes?.lanes lists each lane's directions, and the one to follow
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}

• Each lane carries its directions and, on the lanes to take, the follow direction. The route with guidance example draws them as a small SVG sign in its own code.
• A section leads to the last instruction inside it or, when it ends at a stop line up to 100 m short of the junction, to the next one after it. Where several lead to one instruction, the closest wins, so the lanes go with one step.
• Returns LaneSectionProps | undefined: undefined for a maneuver no section leads to, and for all but the first of the instructions sharing a point, such as a roundabout’s exit after its entry.

Route progress

These helpers read the route’s progress points, which routes have by default. Between two points, values follow the line’s length rather than its vertex count, because vertices crowd into bends. Equal steps of distance cover equal ground, which is what an animation along the route needs.

calculateProgressAtRoutePoint

The distance and time from the start at a coordinate index:

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import { calculateProgressAtRoutePoint } from '@tomtom-org/maps-sdk/core';
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const progress = calculateProgressAtRoutePoint(route, 10);
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// { distanceInMeters, travelTimeInSeconds } | undefined

Returns RouteProgressAtPoint | undefined: undefined when the index is out of range, the route has no progress, or the progress points around the index lack a value.

getRouteProgressBetween

The progress at two coordinate indices and the difference between them:

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import { getRouteProgressBetween } from '@tomtom-org/maps-sdk/core';
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const segment = getRouteProgressBetween(route, 5, 20);
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if (segment) {
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    console.log(`${segment.delta.distanceInMeters} m, ${segment.delta.travelTimeInSeconds} s`);
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}

Returns RouteSegmentProgress | undefined: { start, end, delta }, or undefined when either index cannot be interpolated.

getRouteProgressForSection

getRouteProgressBetween over a section’s startPointIndex and endPointIndex, or those of any { startPointIndex, endPointIndex }, such as the one getSectionOverlap returns:

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import { getRouteProgressForSection } from '@tomtom-org/maps-sdk/core';
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for (const section of route.properties.sections.traffic ?? []) {
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    const progress = getRouteProgressForSection(route, section);
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    if (progress) console.log(`Incident from ${progress.start.distanceInMeters} m, ${progress.delta.travelTimeInSeconds} s to cross`);
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}

Returns RouteSegmentProgress | undefined, as getRouteProgressBetween does.

getCoordinateAtRouteProgress

The position and progress at a point you give as exactly one of elapsed time, distance travelled or a clock time.

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import { getCoordinateAtRouteProgress } from '@tomtom-org/maps-sdk/core';
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const byTime = getCoordinateAtRouteProgress(route, { traveledTimeInSeconds: 600 });
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const byDistance = getCoordinateAtRouteProgress(route, { traveledDistanceInMeters: 5000 });
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// Elapsed time counted from route.properties.summary.departureTime
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const byClock = getCoordinateAtRouteProgress(route, { clockTime: new Date('2025-06-01T09:10:00Z') });
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if (byTime) console.log(`After 10 min: ${byTime.position}, ${byTime.distanceInMeters} m`);

• Values beyond either end of the route return its first or last point.
• Returns RouteCoordinateAtProgress | undefined: { position, travelTimeInSeconds, distanceInMeters }, or undefined when the route has no progress, a clock time is given but the route has no departureTime, the clock time is before the departure, or the progress points lack a value.

getProgressAtNearestRoutePoint

Snaps any location to the nearest point on the route and returns the position and progress there, for hover or click interactions:

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import { formatDistance, getProgressAtNearestRoutePoint } from '@tomtom-org/maps-sdk/core';
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map.mapLibreMap.on('mousemove', (event) => {
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    const nearest = getProgressAtNearestRoutePoint(route, event.lngLat.toArray());
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    if (nearest) console.log(`${formatDistance(nearest.distanceInMeters)} from the start`);
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});

• The location is any HasLngLat: a [longitude, latitude], a GeoJSON Point or a Point feature such as a place.
• Returns RouteCoordinateAtProgress | undefined: undefined when the route has no progress or fewer than two coordinates, or the progress points around the snapped position lack a value.