OSRM (Open Source Routing Machine) is an open-source routing engine that provides interactive route planning, turn-by-turn navigation, and network analysis. It was developed by Project OSRM and is one of the most widely used open source routing engines.

In short, OSRM is a tool that allows you to quickly and easily calculate the optimal route between two points on a map. It can be used to calculate the fastest or shortest route between two points and it can also be used to analyze entire transportation networks.

OSRM is built on the OpenStreetMap (OSM) dataset and it uses an efficient graph structure to quickly determine the best route for a given start and end point. With OSRM, you have the option to store the computed route as a GPX file or output it as GeoJSON.

OSRM is used in many areas, such as navigation apps and web services, logistics, transportation and mobility planning, or tourism analysis.

Example of use cases:

1. Navigation Apps: OSRM can be used by navigation apps to provide real-time route information to its users.

2. Logistics: OSRM can be used by logistic companies to optimize their delivery routes and delivery schedules.

3. Transportation planning: OSRM can be used by urban planners to study the network and design better public transportation systems.

4. Tourism analysis: OSRM can be used by tourism organizations to analyze popular tourist spots and design more efficient tourist routes.