  This article addresses the emergent phenomenon of carto-vandalism, the
intentional defacement of collaborative cartographic digital artefacts in the
context of volunteered geographic information. Through a qualitative analysis
of reported incidents in WikiMapia and OpenStreetMap, a typology of this kind
of vandalism is outlined, including play, ideological, fantasy, artistic, and
industrial carto-vandalism, as well as carto-spam. Two families of
counter-strategies deployed in amateur mapping communities are discussed.
First, the contributors organise forms of policing, based on volunteered
community involvement, patrolling the maps and reporting incidents. Second, the
detection of carto-vandalism can be supported by automated tools, based either
on explicit rules or on machine learning.
