Many of the pressing problems of today have a geo-spatial component. The paper by MacEachren rightly points out the challenges in dealing with efficient representation of Geospatial data. In the last 11 years since the paper was written, radical changes have taken place in the domain of virtual mapping. Not only did GIS softwares like ArcGIS and QGIS develop rapidly, other mapping and Virtual Earth services like Google Maps and Google Earth have also become popular. The authors had rightly pointed out the changes that were taking place since the internet became the prominent medium for disseminate geospatial data.
With 80% of all user-generated data on the web containing geo-location information, storing and leveraging this data generates a lot of interest. Some of the problems discussed in the paper have been efficiently dealt with in the recent years. For example, multi-scale representations of objects have been handled with the concept of scale-dependent renderers used extensively in GIS packages as well as in Google Maps and Google Earth. However, the decision of what to show at each scale is still subjective. When Geographic objects are stored in the database as vectors, attribute information can be added to each of the objects to further describe it in a non-spatial manner. The abstraction of layers provide the flexibility of modularising map building and analysis approach, enabling reuse of the layers to create different themes. Crowd Sourcing and mobile mapping applications have defined the way group mapping tasks are performed.
The paper also emphasises several times on the need for cross domain research to address the problem of Geovisualization and spatial analysis. In terms of Geovisualization, research results from the field of Computer Graphics, Geo-sciences, Cartography, Human Computer Interaction and Information Visualization needs to be integrated in order to find new and innovative ways of creating maps. Multi-disciplinary crosscutting research is the way forward to make further advances in how geographic information is presented.
-Dipto Sarkar