When you want to display a path connecting several locations on a map, a polyline is the tool of choice. In mapping libraries like Leaflet.js, a polyline is a continuous line composed of multiple coordinate points. This is especially useful for visualizing routes, such as walking tours, delivery paths, or public transit lines. By connecting the dots between start and end locations, polylines make it easy to see the overall route at a glance.

In practical terms, route maps are used in many real-world applications:

• Delivery services plot routes for drivers;
• Event organizers show race courses;
• Travel apps display suggested itineraries.

Markers are often added at the start and end points, giving users clear reference points for where a journey begins and ends. With Leaflet.js, you can easily combine polylines and markers to build interactive, informative maps that help users navigate and understand routes visually.