Visualisation Design

“Cartography is about representation” MacEachren (2004). The functionality of a map needs to be taken into account when designing visualisations. Artistic design does not necessarily mean good design and the release of the 1972 subway map of New York (See Figure 1.12) was met with mixed reactions. The design was innovative because it re-imagined the subway system but passengers and visitors could not easily grasp their location by looking at the map. Standardisation could be considered as important to visualisation design, because designer interpretation will vary. Standardisation helps to increase functionality because it focuses on the creation of practises that are most effective for visualisation design. However, cartographers disagree with this idea preferring to form an objective view based on the visualisation they were designing Robinson (1952) and Robinson (1973). The audience a particular visualisation is aimed at would generally dictate how the end product looks.

39 Figure 1.12 Massimo Vignelli’s 1972 New York subway map

MacEachren (2004) produced a simple diagram depicting the process a cartographer undertakes in producing a map. Figure 1.13 shows this diagram and you can see that the recipient is the final link in the design-chain. In other-words, it appears that end users have no input into design. Cartographers saw visualisations as communication tools to be analysed by recipients (Kolacny, 1969). Modern cartographers are now adopting what was previously referred to as a representational approach (MacEachren, 2004) or a user-centered design approach when it comes to visualisation design. Research has been carried out to highlight the necessity of user input and modern visualisation design will be discussed in the next paragraph. Diversity of the user perspective is an inherent difficulty when attempting to communicate through visualisation. Broad interpretations of map detail can occur. Howard (1980) discusses an objective approach to incorporate user related issues including; cultural, psychological, and required communication processes for symbols. Adding to this, perception is a factor in visualisation design as it is linked to user interpretations, or how a user perceives a visualisation. Consider perception as a representation of what we see with our eyes and cognition as the objects and relationships within that scene. You will see that map objects such as symbols are not the only concern cartographers should focus on when designing their representations (MacEachren, 2004).

As already mentioned user interpretation of representations will vary between each user. This complicates the ability of the communication model in Figure 1.13 to function effectively. If a user will create assumptions on what a visualisation depicts, then user derived meaning may

40 never correlate with the designers. To aid with map comprehension, Pinker’s framework (1990) on graphical comprehension can be considered as a useful tool.

Figure 1.13 Schematic depiction of cartography as a process of information communication (MacEachren, 2004)

Modern Visualisation Design needs to incorporate users in a more meaningful way. This is because a significant proportion of visualisation design problems are related to users. A similar question that was asked about the usefulness of geovisualisation can be repeated. “What is a visualisation good for?” Haklay and Tobon (2003) discussed how we understand the diversity in human behaviour when dealing with graphic visualisations. Research carried out by Wilson et al. (2010) on personalising visualisations shows that we need to account for user differences. This thesis addresses these issues and are discussed in the Experiment Design chapters.

Thematic maps are also used for the acquisition of mapped information. A map conveys information and map creation should follow the model process shown in Figure 1.14. This model was applied during this research, particularly during the experiment design stage to ensure data was appropriately displayed for the end users. Thematic maps should also be considered as a significant piece of interactive visualisation. They are a staple of visualisations to which other types of visualisations are linked.

Geographic Environment

Cartographers

41 Figure 1.14 Basic Steps for communicating map information to others (Slocum et

al., 2009)

You can split visualisation into two different definitions. The first is geographical visualisation. ‘Geographical visualisation [can be defined] as the use of concrete visual representation, whether on paper or through computer displays or other media, to make spatial contexts and problems visible, so as to engage the most powerful human information-processing abilities, those associated with vision’ (MacEachren, 1992). The second is based around MacEachren’s (1994) Visualisation Cube, displayed in Figure 1.15. MacEachern’s argument considered geographic visualisation as a private activity and communication a public activity. The private activity would be highly interactive, while the public would be the opposite, where knowns are presented. More recently the phrase geographic visualisation has been replaced by geovisualisation (MacEachren et al. 1999), and this has become the standard term used. Cyber-cartography was a proposed term by Taylor (1997), and it incorporates some of the elements of geovisualisation such as ‘highly interactive user engagements’ and ‘new research partnerships’. In modern day terms we could describe these types of visualisation as online

42 interactive visualisations. These types of visualisations are an increasingly important driving force behind geographical visualisation advancement.

Figure 1.15 MacEachren’s Visualisation Cube (1994)

The importance of visualisations in the advancement of our understanding and analysis of complex data is evident, but it is also crucial to have an adequate set of tools to carry out analysis on data. The next section will discuss the type of visualisations that can be used to successfully carry out the first experiment of this thesis.