Future Internet_**2012**, \(4\), 285-305; doi:10.3390/fi4010285  
_future internet_  
**ISSN 1999-5903**  
www.mdpi.com/journal/futureinternet  
_Article_  
**Characteristics of Heavily Edited Objects in OpenStreetMap**  
**[PERSON] \({}^{1,\star}\) and [PERSON] \({}^{2}\)**  
\({}^{1}\) Department of Computer Science, National University of Ireland, Maynooth, Ireland  
\({}^{2}\) School of Computer Science and Informatics, University College Dublin, Dublin, Ireland;  
E-Mail:[EMAIL_ADDRESS]  
\({}^{\star}\) Author to whom correspondence should be addressed; E-Mail: [EMAIL_ADDRESS];  
Tel. : +353-1-268-0100. _Received: 30 January 2012; in revised form: 7 March 2012 / Accepted: 16 March 2012 /_  
_Published: 20 March 2012_  
**Abstract:** This paper describes the results of an analysis of the OpenStreetMap (OSM) database for the United Kingdom (UK) and Ireland (correct to April \(2011\)). \(15,640\) OSM ways (polygons and polylines), resulting in \(316,949\) unique versions of these objects, were extracted and analysed from the OSM database for the UK and Ireland. In our analysis we only considered \"heavily edited\" objects in OSM: objects which have been edited \(15\) or more times. Our results show that there is no strong relationship between increasing numbers of contributors to a given object and the number of tags (metadata) assigned to it. \(87\%\) of contributions/edits to these objects are performed by \(11\%\) of the total \(4128\) contributors. In \(79\%\) of edits additional spatial data (nodes) are added to objects. The results in this paper do not attempt to evaluate the OSM data as good/poor quality but rather informs potential consumers of OSM data that the data itself is changing over time. In developing a better understanding of the characteristics of \"heavily edited\" objects there may be opportunities to use historical analysis in working towards quality indicators for OSM in the future. **Keywords:** OpenStreetMap; collaborative editing; volunteered geographic information; spatial data Introduction  
Volunteered Geographic Information (VGI), the term coined by [PERSON] [1], is the recent empowerment of citizens in the collaborative collection of geographic information. He argues that VGI has enormous potential to become a \"significant source of geographers' understanding of the surface of the Earth\". Crucially, \"by motivating individuals to act voluntarily, it is far cheaper than any alternative, and its products are almost invariably freely available\". OpenStreetMap (OSM) is a collaborative project to create a free editable map database of the world as is probably the most well known example of VGI [2]. Spatial data is contributed to OSM from: portable GPS devices, tracing shape outlines from aerial photography, import of free spatial data, or simply from local knowledge [3]. [PERSON] _et al_. [4] and [PERSON] [5] provide detailed introductions to the OSM project. Real world geographic objects are represented in OSM as points, lines, and polygons. In OSM these are referred to as nodes and ways. Ways is a collective term for both polylines and polygons. Spatial attributes for these objects are stored as _tags_. An object can be tagged with any number of tags. On the OSM wiki [6] there is a community maintained page (see [7]) detailing the most-popular tags. This amounts to something close to an OSM-community generated ontology for the spatial objects in the OSM database. Volunteers, who collect and contribute data to OSM, have the freedom to add their own arbitrary tags if necessary to annotate their data. However it is usually only the tags listed on the _map features_ list [7] that are supported by GIS software capable of consuming OSM data and cartographic software for rendering OSM data as map image tiles. The growing spatial coverage and high-quality content in OSM [8,9] has branched beyond \"the converted\" and has gained enthusiastic endorsement from the likes of Yahoo, ESRI, MapQuest [10], and Microsoft [11]. Yahoo!