# Automatic Generation of Guidance for Indoor Navigation at Metro Stations
## 5 Discussion  
Urban commuter planners provide comprehensive information on all modes of transport in a city, but they are usually limited to routing functions. At the same time, an increasing number of public buildings are providing indoor navigation systems. Such applications use positioning engines, which, despite research over the past decade, still provide poor positioning accuracy when run on smartphones--widely available devices. A large proportion of indoor navigation systems use turn-by-turn guidance due to the much higher cost of basing navigation guidance on landmarks. This approach, together with a positioning system with poor accuracy, limits the ability to popularise indoor navigation systems in public buildings. The application, which is the result of the research, focuses on pedestrian navigation in metro stations and takes into account the expectations of people with special needs. By design, the application will be used without a positioning engine, and users will determine their location based on the map and landmarks, aided by photographs attached to the route decision points. The authors focused on implementing algorithms to generate navigational directions automatically, and through the support of people with disabilities, it was possible to create an application that works acceptably for the target group. It is still necessary to collect and maintain the spatial database of landmarks, in addition to taking photos and updating them periodically. However, the idea is that automated algorithms help to reduce this cost, as a limited number of landmarks are needed to generate guidance. A natural direction for further development of the system is integration with a positioning system. The lack of presentation of the user's position in the current application can be seen as a drawback because users accustomed to other systems may cease trying to use this application because of this missing function. On the other hand, current positioning algorithms using Wi-Fi networks or Bluetooth beacons offer position detection with low accuracy. A system generating navigation guidance should take into account the accuracy and the characteristics of a calculated position. Hence, integration of the positioning system with the navigation system is not a straightforward task and requires additional research and testing. Navigation guidance must be built in such a way that potential position error does not prevent its interpretation. The system was built with the assumption that the user recognises his surroundings based on the description of the direction and the photo. This should help in the potential integration of the solution; however, the system has not been tested with the positioning engine, which makes it difficult to estimate the work needed. During the development of the algorithm, various rule modifications were considered, and their impact on the final indoor guidance was analysed. In some cases, satisfactory solutions have been developed; in others, specific approaches have been adopted with the expectation that end users will assess their usefulness. When the system is made available, a number of comments from users are expected. The feedback will be analysed and influence the modification of the rule set. Each time a developer decides to provide a change in the spatial data or change in the algorithm's rules, they must consider side effects--how the change impacts other routes. The authors came to the conclusion that predefined navigational directions can improve the system maintenance process. This feature allows one to define a direction explicitly and link it to a decision point. Whenever the algorithm encounters a predefined direction, it breaks the rule-based inference and adopts the direction designed by the operator. This system was intended to be built for stations of the Warsaw Metro, and the authors were focused on creating the best possible solution operating within this scope. This limits the solution to metro stations of a specific architectural construction style and limited complexity.