# Exploring Data Model Relations in OpenStreetMap
## 5 Conclusions and Future Work
### Suggestions for Future Work  
This paper is our first exploration of relations in OSM. Many interesting aspects of relations have emerged. Subsequently, growing from this work, there are a number of interesting areas for future work which are outlined as follows:  
* From our reading of the OSM Wiki [25], more standardised documentation on relations on the OSM Wiki is required. At present, the information on the OSM Wiki is somewhat scattered and disorganized making it a little difficult to consume. We will consider making edits to these Wiki pages in the future. * Visualisation of large relations: Visualisation or rendering of many relations with a large number of members is a difficult computational task. This task often times out on the OSM website. The reasons for this are related to the complex nature of large relations which also contains relations themselves. The rendering of these types of relations in real-time is computationally difficult. * Understanding the complexity of relations: As we discussed above, it is a difficult task to effectively assess and understand the type of spatial and topological relationships which are being represented by a relation in OSM. Membership size of relations could be a useful high level indicator. For example, relations with more members have more spatial and/or topological complexity. However, we believe, further work is required in developing approaches or methodologies to quantitatively assess the complexity of the spatial relations or topological relations expressed by a relation in OSM. This type of work would allow researchers and OSM experts to better assess the situations within OSM where relations are needed. * Contributors and Relations in OSM: In this paper, we have only considered the current version of all of the relations in the four case-study cities. Researchers [35] have considered longitudinal analysis of the contributors to OSM for ways and nodes. A similar study into the history of edits to relations may indicate the characteristics of contributors to create and edit relations. Anecdotally, relations are only created and edited by more experienced contributors to OSM. Are all contributors to OSM actually aware of relations? [PERSON] et al. [50] uses the example of turn restrictions in OSM to state that most users are completely unaware of this type of tagging. Is it the case that only experienced OSM contributors actually work with relations and that the complexity of the relation data object is actually a barrier to wider contributions? Amongst others [PERSON] and [PERSON] [35] show that in OSM the top 10% contributors (ranked by their quantity of contributions) perform over 90% of all object creations and edits. Within this top 10% there are what the authors call \"isolated\" contributors who appear to be working completely on their own without editing the work of other top contributors. Future work is required to investigate if these patterns are also visible within the contribution history on relations in OSM. * Our analysis considered four European cities. An area for immediate future work would include extending this analysis to include more cities and regions with different sizes, populations, OSM communities, etc. The extension of the research in this paper could also include the full edit history of relations in case-study areas. The edit history for relations is also downloadable from the OSM Wiki. We are aware that our selection of cities for the case-studies are the result of personal selection. To indicate the presence of more general trends or patterns we will need to carefully select cities or urban areas based on their urban characteristics or OSM community structure. [PERSON] et al. [52] emphasise the need to ensure that OSM analysis extends beyond the \"typical Anglo-American bias\". They recommend that analysis considers a diverse set of national and regional OSM communities. We believe that this is the first academic paper to report the results of a study into relations in OSM.