In the course of their long history, maps have been successively monopolized by various corporations which have developed new practices and purposes for them. For example, while the foundations of modern geography were laid by Ptolemy as early as the 2nd Century AD, T-O maps (or Orbis Terrarum) were a driving force for a religious cosmogony throughout most of the Middle Ages. In the 19th Century, topographic cartography evolved into thematic cartography as the geographers’ monopoly opened up to include engineers and doctors.

Recently, map digitization through geographic information systems (GIS) has shifted the monopoly of maps to computer scientists. While early GISs were largely viewed as overly technical, online maps indicate the advent of a change of direction in terms of monopoly. However, if we scratch the surface of the advertising narrative, which claims that the Internet is operating a “democratization” of mapping, we can enquire into which professions and audiences can now appropriate maps.

Creating online maps requires a programming interface or an application programming interface (API), which makes possible not only the display of a map on a Webpage, but also, most importantly, the visualization of personal or third-party data on a map. This operating mode is always accompanied by technical mutations and new online practices. The overlap of a base map with third-party data sources, called “mashup”, uses the same technical architecture as other applications ...

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