EEO-AGI Scotland Seminar Review : Prof Jason Dykes : 17th Jan

Members of Edinburgh’s GIS community gathered on 17th January in the Old Library at the School of GeoSciences in Drummond Street, where Professor Jason Dykes, of the giCentre, City University London, delivered a seminar exploring “Cartographic Information Visualisation”. Full of elegant and dynamic design solutions to spatial data problems, the well-attended presentation provided an interesting insight into the work that Professor Dykes and his colleagues at the giCentre produce.

Although design in relation to cartography and data visualisation has been a topic of discussion for some time, developments in technology have allowed designers to become more experimental and has opened up fantastic new ways to display and explore spatial data and cartographic design. The first example of this that Professor Dykes mentioned was in relation to the traditional map legend. Since the days of paper maps, the legend has appeared as a static box explaining the symbology used in the map in an order that the cartographer, or some standard has deemed appropriate. But what is the optimal way to represent the legend, and in how should it be ordered? Arguably this is dependent on the map’s use, which may vary from user to user. Prof. Dykes demonstrated how legends could become dynamic in a digital mapping environment as they can be quickly changed from a hierarchically ordered legend at the side of a map, to a spatial legend where symbology is highlighted at the geographical space in which an example of it occurs.

Professor Dykes went on to discuss how, although the spatial dimension of data is important, some distortion of space is often required to optimally visualise the data. Consider the cartogram and the choropleth map: although the cartogram will distort the geographical location, it is likely that this will convey trends and patterns in the data much better than the choropleth map which is constrained by geography. Treemaps use this idea to display hierarchical data, in a way that can be easily compared, using partial geographies. Professor Dykes demonstrated how these types of hierarchical visualisation can be used to detect complicated spatial patterns at various scales in equally varied applications. One of the most interesting examples of this was an investigation he and colleagues had carried out regarding the potential for ‘name bias in alphabetically ordered ballot papers’. In this example Professor Dykes showed how there can be trends in a dataset that are not apparent when viewed at a coarse scale, or when ordered in a particular way, that become so when viewed at a finer scale, or in a different order. The visualisation also showed how although overall there may not have been any indication that the order of names affected elections in London as a whole, in some peripheral boroughs it is likely that this is the case.

The seminar covered several other visualisation issues that were overcome by clever design, such as Irish migration, a video about which can be viewed here:

In his presentation, Pofessor Dykes alluded to the work of Swiss artist and comedian Ursus Wehrli, who ‘tidies’ art by bringing systematic order to well known pieces. Like these ‘tidied’ works of art, good design for data visualisation brings together art and structure creating something that is both aesthetically pleasing, meaningful and easily understood. Professor Dykes and his colleagues have produced fantastic examples of great cartographic information visualisation, which can be viewed on the giCentre website (

Links to all the resources Professor Dykes referred to throughout the seminar can be found here:

Charlotte Graves
(MSc in GIS at University of Edinburgh)


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