Completeness in volunteered geographical information – the evolution of OpenStreetMap coverage (2008-2009)
13 August, 2010
The Journal of Spatial Information Science (JOSIS) is a new open access journal in GIScience, edited by Matt Duckham, Jörg-Rüdiger Sack, and Michael Worboys. In addition, the journal adopted an open peer review process, so readers are invited to comment on a paper while it goes through the formal peer review process. So this seem to be the most natural outlet for a new paper that analyses the completeness of OpenStreetMap over 18 months – March 2008 to October 2009. The paper was written in collaboration with Claire Ellul. The abstract of the paper provided below, and you are very welcome to comment on the paper on JOSIS forum that is dedicated to it, where you can also download it.
Abstract: The ability of lay people to collect and share geographical information has increased markedly over the past 5 years as results of the maturation of web and location technologies. This ability has led to a rapid growth in Volunteered Geographical Information (VGI) applications. One of the leading examples of this phenomenon is the OpenStreetMap project, which started in the summer of 2004 in London, England. This paper reports on the development of the project over the period March 2008 to October 2009 by focusing on the completeness of coverage in England. The methodology that is used to evaluate the completeness is comparison of the OpenStreetMap dataset to the Ordnance Survey dataset Meridian 2. The analysis evaluates the coverage in terms of physical coverage (how much area is covered), followed by estimation of the percentage of England population which is covered by completed OpenStreetMap data and finally by using the Index of Deprivation 2007 to gauge socio-economic aspects of OpenStreetMap activity. The analysis shows that within 5 years of project initiation, OpenStreetMap already covers 65% of the area of England, although when details such as street names are taken into consideration, the coverage is closer to 25%. Significantly, this 25% of England’s area covers 45% of its population. There is also a clear bias in data collection practices – more affluent areas and urban locations are better covered than deprived or rural locations. The implications of these outcomes to studies of volunteered geographical information are discussed towards the end of the paper.
3 August, 2010
The process of academic publication takes a long time, so only now my paper from 2008 is finally in print.
So the paper, which should be cited as:
“Haklay, M., 2010, How good is volunteered geographical information? A comparative study of OpenStreetMap and Ordnance Survey datasets” Environment and Planning B: Planning and Design 37(4) 682 – 703″
It’s abstract is:
Within the framework of Web 2.0 mapping applications, the most striking example of a geographical application is the OpenStreetMap (OSM) project. OSM aims to create a free digital map of the world and is implemented through the engagement of participants in a mode similar to software development in Open Source projects. The information is collected by many participants, collated on a central database, and distributed in multiple digital formats through the World Wide Web. This type of information was termed ‘Volunteered Geographical Information’ (VGI) by Goodchild, 2007. However, to date there has been no systematic analysis of the quality of VGI. This study aims to fill this gap by analysing OSM information. The examination focuses on analysis of its quality through a comparison with Ordnance Survey (OS) datasets. The analysis focuses on London and England, since OSM started in London in August 2004 and therefore the study of these geographies provides the best understanding of the achievements and difficulties of VGI. The analysis shows that OSM information can be fairly accurate: on average within about 6 m of the position recorded by the OS, and with approximately 80% overlap of motorway objects between the two datasets. In the space of four years, OSM has captured about 29% of the area of England, of which approximately 24% are digitised lines without a complete set of attributes. The paper concludes with a discussion of the implications of the findings to the study of VGI as well as suggesting future research directions.