Exploring cartographic design in social-network map mashups

Online mapping landscapes have never been as rich or diverse yet this challenges cartography as new map makers present their work often eschewing long-established cartographic conventions. Blogs, micro-blogs and online forums are used to communicate ever more and maps are becoming an important part of that online world. The way that this information is mapped is often poor and based on little more than placing a geometric symbol at an imprecise geo-located point. Symbols often overlap, are poorly scaled and conflict with both each other and the map background. In this paper, we explore why many map mashups of social network data fail to communicate. We then explore what value can be extracted from the social network site Twitter that might be represented spatially and how the data can be used purposefully. We develop a range of maps using the ArcGIS javascript API in concert with Open Streetmap data and Arc Server map services to develop web maps for effective communication. We deal with the cartographic issues caused by mapping tweets at coincident points, representing the temporal dimension of the data and developing suitable designs to more effectively visualize Twitter feeds.