Temporal Analysis on Contribution Inequality in OpenStreetMap: A Comparative Study for Four Countries
1
College of Electronic Science and Engineering, National University of Defense Technology, Changsha 410073, China
2
GIScience Research Group, Institute of Geography, Heidelberg University, Berliner Street 48, Heidelberg D-69120, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: Wolfgang Kainz
ISPRS Int. J. Geo-Inf. 2016, 5(1), 5; https://doi.org/10.3390/ijgi5010005
Received: 11 September 2015 / Revised: 30 December 2015 / Accepted: 31 December 2015 / Published: 18 January 2016
Contribution inequality widely exists in OpenStreetMap (OSM), which means that most data come from a minority of the contributors, while the majority only accounts for a small percentage of data. This phenomenon is of great importance to understanding from where the data come and how the project evolves. The investigation in this paper is dedicated to answering the following questions: How does contribution inequality change over time in OSM? Which group of contributors plays a more important role in influencing trends in contribution inequality: the “vocal minority” or the “silent majority”? To answer the first question, we provide overall measurements for contribution inequality using the Lorenz curve and the Gini coefficient. To answer the second question, we use quantile-based classifying strategy to analyze structural changes in the community, and use the Mann-Whitney-Wilcoxon test to analyze productivity changes. Our case study shows that in countries without significant imports, contributions become more unequal over time. This trend is consistent with the rapid expansion of the silent majority, even though other classes of contributors also grow at a slower pace. On the other hand, contribution inequality fluctuates a lot in countries with huge imports, and agrees well with the productivity changes in the vocal minority.
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MDPI and ACS Style
Yang, A.; Fan, H.; Jing, N.; Sun, Y.; Zipf, A. Temporal Analysis on Contribution Inequality in OpenStreetMap: A Comparative Study for Four Countries. ISPRS Int. J. Geo-Inf. 2016, 5, 5.
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