Collaborative mapping
Collaborative Mapping is the aggregation of Web maps and User-generated content, from a group of individuals or entities, and can take several distinct forms.
Map types
Collaborative Mapping applications vary depending on which feature the collaborative edition takes place: on the map itself (Map generation), or on diverse overlays to the map (Map annotation).
Map Generation
In this kind of application, the map itself is created collaboratively. In some cases, users may utilize their GPS devices, like on OpenStreetMap. Collaborative mapping and specifically map generation faces the same problems as revision control, namely concurrent access issues and version merging. In addition to these problems, collaborative maps must deal with the difficult issue of cluttering, due to the geometric constraints inherent in the media. One approach to this problem is using overlays, only a few online mapping systems, such as MapWith.Us, use overlays to deal with clutter and revision control. Overlays group to together items on a map, allowing the user of the map to toggle the overlay's visibility. If each user's revisions are contained in an overlay, the issue of revision control and cluttering can be mitigated.
Map Annotation
In this case, the application uses map tiles from a third-party (for example one of the mapping APIs) and adds its own collaboratively-edited overlays to them, sometimes in a Wiki fashion. For example WikiMapia adds user-generated place names and descriptions to locations. A very simple Collaborative Mapping application would just plot users' locations (Social mapping or Geosocial networking) or Wikipedia articles' locations (Placeopedia).
Collaborative implies the possibility of edition by several distinct individuals so the term would tend to exclude applications such as Wayfaring where the maps are not meant for the general user to modify.
Commercial context
The dichotomy between corporate projects and user-driven projects is important in Collaborative Mapping. [1]
Corporate Initiatives
Several big internet companies launched mapping applications with collaborative features, most importantly Google Maps with the My Maps feature.
Thematic Contexts
Such applications have a lot of possible contexts they can be used in: daily life (transportation, shopping), travel, culture, business, social, etc.