Explore the inside of buildings

With cartes.app, you can navigate through the myriad of indoor maps maintained by the OpenStreetMap community.

published on March 19, 2026

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Using cartes.app, you will now see a banner informing you that the current view includes indoor maps. Click "Yes", and the complex worlds of train stations, shopping centers, museums, and universities will no longer hold any secrets for you.

A palette of commands allows you to jump from floor to floor, list them, or even hide these indoor maps.

Why don't we display these indoor maps by default? Because they significantly increase the amount of data to download to display the map. Not to mention the code itself (we call it a "library") that allows displaying the maps, which weighs its share of bytes, adding more seconds of delay on a weak 4G connection.

How does it work?

We use the IndoorEqual project, a French, free, and open-source indoor mapping project. It hosts itself the indoor data we use. Thanks to François de Metz for his valuable work.

Which places have indoor maps?

A myriad of places around the world already have indoor maps, thanks to the collaborative effort of the OpenStreetMap project on which cartes.app relies. If you are interested in contributing, you can learn all about it on this page.

In particular, SNCF (the French public train station operator) has agreed to publish all the maps of its train stations on OpenStreetMap, as you can discover in this presentation. And it's not alone: the OpenStreetMap community allows SNCF and Transilien (the trains of Paris, separate from SNCF) to collaborate on train stations.

But train stations are far from the only interiors mapped, as anyone can contribute! On this map, you can explore the areas of the world that have indoor maps: for example, the Port-Museum of Douarnenez, a cute Breton harbor.

Better than Google & Apple Maps

Despite their billions of euros in annual budget, the maps of the big tech companies don't seem to be at all up to par on this subject.

Not only do neither Google nor Apple offer indoor maps of the Rennes train station pictured in this article's cover image, but their coverage on this subject is particularly poor.

Google's view: so many points of interest are missing in the station

Apple's view: it's simply nonsensical

Cartes.app's view via OpenStreetMap: precise, rich, floor by floor

Is it due to a lack of data? A lack of interest in French train stations? Or a lack of advertising paid by station merchants?

A clue: large airports are perfectly mapped by Google and Apple Maps. A testament to the American bias on the subject, a country where people take planes as often as French buy their croissants?

These are black boxes, so it's hard to know. But what is certain is that this shows that by working together, European actors can do much better than the big tech.

What we plan for the near future

This version of indoor maps is only our v2. In upcoming versions, we plan several improvements.

Pedestrian route calculation within buildings

The library we use for route calculation in public transport already has the capability to compute routes inside buildings. This is very useful in metropolitan areas where train or metro stations often have multiple floors.

Display of Panoramax street photos to explore floors in 360° photos

Our colleagues at Panoramax are already working on it!

Demo of indoor photos

3D view: overlaying floors

Some SNCF train stations already have 3D plans. Without going as far as this artistic view, we could simply represent the plans of the 1st floor 3m above the ground, etc.

Rennes train station

Your ideas!

Share your innovation ideas for better indoor maps with us.

If you're a developer, don't hesitate to join us.