Following our first post on the challenges and opportunities of an indoor-extended OpenStreetMap, we now wish to concentrate on the specifics and provide a proposal for “OpenIndoorMaps”. Before doing this, we provide some use-case scenarios that our proposal addresses.

Use-Case scenarios for OpenIndoorMaps

There are many possibilities or use-case scenarios for indoor maps or services such as routing or navigation. Imagine being a businessman at the airport: after entering the entrance hall you first want to go to the check-in counter and then to a nearby newspaper shop before searching for the lounge and then finally going to the gate. Normally you have to do this “navigation” by yourself, which can be quite a challenging task (especially in huge airports such as Chicago or Beijing).

Another example is the following: you are visiting a huge shopping mall. Unfortunately you do not have much time, thus you need proper guidance inside the mall. Luckily, you have your OSM based indoor routing application on your mobile phone, which means that you can easily locate your desired shop or item and receive proper routing instructions inside the mall. Besides these two use-cases there are plenty of other scenarios such as navigation in hotels (imagine being in Dubai in the Burj Khalifa with more than 100 floors or in the Venetian Resort in Las Vegas with more than 7000 rooms), in universities, in museums, train stations and so on.

As you can see, there are many meaningful examples of why indoor information is so important.

The indoorOSM model proposal

Basically, a building is represented as a feature (technically as a “relation”), whereby an attribute characterises it as building. One of the well known features of OSM is the fact that all kinds of additional building information such as the name or type can be attached to it. Every floor within the building is assigned a floor level while every entrance or exit of the building receives a unique ID in order to create a connection between the outdoor world and the indoor. Each floor is then assigned a corresponding level, (“floor-relation member”) such as level_0, level_1, level_-1 and so on (level_0 always denotes the ground floor).

Each floor of a building (technically each relation-member of the main relation) is again mapped separately, whereby a specific floor level is selected during the editing session.

Different building parts of a floor are mapped as room, hall, corridor, and so on. Each part of the building can contain features such as windows which can be described (tagged) in detail. Vertical connections are mapped as elevators, stairways and so on. A vertical connection can be connected to several levels (e.g. an elevator) or a single level (stairs).

Extend the model to your needs!

A full technical description can be found here: http://wiki.openstreetmap.org/wiki/IndoorOSM. Please do not hesitate to come up with proposals on how to improve and extend the model!

Start mapping a building yourself!

Start mapping a building yourself: Just open the JOSM editor, zoom to the location where the building is and start mapping the level shell as well as the building parts of one level (for example the ground level), and finally combine them in a relation. Afterwards, you can hide this relation (thus all ways will be invisible) and start with the next floor. When you have finished mapping all of the floors, simply create the building relation and add all floor-relations as relation-members.

Look at your result!

Currently, there is no automated integration process of indoor maps into http://indoorosm.uni-hd.de. Therefore, if you have mapped a building, simply send a short notification to m.goetz [at] uni-heidelberg.de (mentioning the relation id of your building) and your map will be integrated as fast as possible.  In the long run, a version with automated building integration can also be developed – assuming that there will be more and more building mapped indoors.

In most countries, OpenStreetMap played catch-up with the commercial maps. Indoor Maps are a completely new playing field. So far, none of the commercial providers have gained traction in the Indoor space. It is also an area where OpenStreetMap could take the lead and leave the commercial providers behind straight from the beginning. Wishful thinking? Maybe, maybe not. On the one hand, there is a lack of an Indoor approach for OpenStreetMap. On the other hand, there is no other map data with such attention to detail.

Now there is also a very promising approach to Indoor Maps for OpenStreetMap by the University of Heidelberg and especially Marcus Götz, who is co-author of this post and who will present his approach in a succeeding post. In this post, we want to give a better idea of the opportunities and challenges for “OpenIndoorMaps”.

The opportunity

Germany has reached a leading position with regard to coverage in the OpenStreetMap universe. Around the Reichstag in Berlin, every single tree is mapped. In the Berlin zoo, every single animal compound is mapped. So, what’s next for mappers in those densely mapped areas? An obvious answer is to go indoors.

The indoor space is the last frontier in mapping, and people are seeking and even expecting their well-known outdoor applications (e.g. navigation or local search) being adapted to the Indoor context. However, for transferring applications like openrouteservice.org or osm-wms.de indoors requires details about indoor spaces, and buildings need to be mapped inside. This is where the OSM community can build upon their strength of local knowledge and their attention to detail and as a result beat commercial data providers.

The key difference

Indoor applications require maps on top of each other to deal with floors. Floors need to be connected to each other. Floors need to be considered during capturing and during rendering. Different data is overlaid with each other, thus an appropriate methodology for capturing and visualizing the data is required. Especially a tall  building with several floors results in many super-imposed ways when mapping the rooms, corridors and floor shapes in OSM, which makes the OSM mapping some kind of inconvenience (at least for inexperienced mappers). Mapping indoors results in a huge amount of data for a comparable small area.

The challenges

Capturing and rendering floors – How can different floors be mapped in OSM? What is an appropriate visualization of multi-level buildings? How can the OSM map be extended for indoor information?

Privacy protection – Can the indoor space be mapped without limitation or are their additional privacy concerns to be considered?

Indoor Measurement – What technology do people need to capture indoor maps? Which gadgets will take over the role of the GPS receiver for street maps? Is there some kind of publically accessible building information available?

The Indoor Approach by the University of Heidelberg

The Indoor Approach of the University of Heidelberg focuses on dealing with the concept of floors. Thereby, each floor is mapped in great detail, thus the shapes and geometry of rooms are also included. The developed approach builds upon the existing OSM technology with ways and nodes, and combines them with relations to a building. Additional information about doors or semantic information, such as room names, is also included.  Essentially, a building can be fully mapped with existing OSM editors (mainly Potlatch or JOSM) and no additional extensions are required. Similar to other applications, the data can then be used for the creation of indoor maps and other applications.

Part 2 of this post will describe the approach in more detail and intends to encourage a discussion to include the community in development of a feasible approach for the OpenStreetMap community.