The comprehension of folksonomies is of high importance when making sense of Volunteered Geographic Information (VGI), in particular in the case of OpenStreetMap (OSM). So far, only little research has been conducted to understand the role and the evolution of folksonomies in VGI and OSM, which is despite the fact that without a comprehension of the folksonomies the thematic dimension of data can hardly be used. A recently published article (Mocnik et al. 2017) examines the history of the OSM folksonomy, with the aim to predict its future evolution. In particular, inspired by Ballatore and Zipf (2015) it is explored how the documentation of the OSM folksonomy relates to its actual use in the data, and the historical and future scope and granularity of the folksonomy is investigated. Finally, an interactive visualization technique is proposed to examine the folksonomy in more detail.
In particular, the following research questions (RQ) have been adressed:
RQ1:
Acknowledging that there is no formal requirement to document the folksonomy, how does the folksonomy used in the OSM data-set relate to its documentation in the OSM wiki? This question is of particular interest because the documentation of the folksonomy is easy to analyse, while the analysis of the folksonomy used inside the OSM data-set would require extensive computation power and a more sophisticated statistical examination. This question is addressed by comparing when key-value pairs were first used in the data, and when they were first documented.
RQ2:
More and more key-value pairs are introduced over time. How did the OSM folksonomy change in the past, and how will it evolve in the future? In particular, the aim is to showing that only a limited number of keys and values will be introduced if current trends continue, and this number of keys and values is estimaed. This approach renders possible an understanding of how the scope of OSM folksonomy may evolve, and how fine-grained the representation will become.
RQ3:
The scope of the folksonomy can be expected to increase over time, and the folksonomy can be expected to become more fine-grained and to be increasingly documented. Can we identify several phases in the evolution of the OSM folksonomy? RQ1 and RQ2 aim at understanding the changing scope, granularity, and documentation in more detail.
RQ4:
The OSM folksonomy is complex and subject to regular modifications. Many decisions to modify the folksonomy, or its documentation, result from the need for new values, or even from planning processes. These factors can be understood by manually retracing when new values were introduced, or when values were deprecated. How can we visualize the OSM folksonomy in order to understand its evolution at the level of individual keys and values? The authors are not aware of any already available visualization of the history of the OSM folksonomy. A new visualization technique is proposed, which is able to address this research question.
The results and a discussion are presented in the paper ( Mocnik et al. 2017).
Live Demo interactive visualization OSM Tags Wiki history: http://osm-vis.geog.uni-heidelberg.de/
Mocnik, F.-B.; Zipf, A., Raifer, M. (2017): The OpenStreetMap folksonomy and its evolution. Geo-Spatial Information Science. GSIS. Volume 20, 2017. Pages 219-230. http://dx.doi.org/10.1080/10095020.2017.1368193
earlier work:
A. Ballatore & A. Zipf (2015) A Conceptual Quality Framework for Volunteered Geographic Information, Spatial Information Theory (COSIT), Santa Fé, NM, pp. 89–107. [web] [pdf]