The route whose properties.progress is interpolated.
The progress array must cover the requested index, so the first entry's
pointIndex must be ≤ pathIndex and the last's ≥ pathIndex.
Zero-based index into the route's coordinate array.
The interpolated RouteProgressAtPoint, or undefined when:
progress datapathIndex is outside [0, coordinates.length - 1]pathIndex falls outside the range covered by the progress entriesconst progress = route.properties.progress;
// progress = [
// { pointIndex: 0, distanceInMeters: 0, travelTimeInSeconds: 0 },
// { pointIndex: 50, distanceInMeters: 2500, travelTimeInSeconds: 120 },
// { pointIndex: 100,distanceInMeters: 5000, travelTimeInSeconds: 300 }
// ]
// With vertex 25 halfway along the line from vertex 0 to vertex 50:
const result = calculateProgressAtRoutePoint(route, 25);
// result = { distanceInMeters: 1250, travelTimeInSeconds: 60 }
Interpolates the cumulative traveled distance and time at an arbitrary point on the route path.
Between the two RouteProgressPoint entries around
pathIndex, the values follow the line's length rather than its vertex count, because vertices crowd into bends and thin out on straights.