Discovery exhibition: using spatial treemaps in local authority decision making and reporting

At Leicestershire County Council we are using spatial treemaps to analyse labour markets and commuting behaviour. This novel visualization technique, presented at InfoVis 2008, has resulted in a number of insights and discoveries. Transport planners in our organization indicate that the graphics are effective and have advantages over alternatives. As researchers in the local authority we report upon using these graphics to inform decision makers and residents in the county’s evidence base for sustainable transport planning

Towards confirmatory data analysis? Deriving and analysing routing information for an origin-destination bike share dataset

Data collected from urban bike share schemes allow observed travel behaviours to be analysed on a uniquely large scale. Exploring such timed origin-destination (OD) data from the London Cycle Hire Scheme (LCHS), we previously generated detailed insights into spatiotemporal patterns of travel and suggested new hypotheses for their motivation. A limitation was that with only the origins and destinations of cycle journeys, little was known about the nature and context of likely cycled routes. In this study, we use the CycleStreets routing engine to derive routing information for every OD pair made through the LCHS. From these suggested routes, we collect heuristics for the nature of each journey. Information on the number of signalled junctions encountered, on any bridges crossed, as well as a proxy for the busyness of suggested routes is recorded. We then analyse over 5 million journeys made by LCHS members during a 12-month period (September 2011 – September 2012). Focussing on LCHS journeys that involve crossing the River Thames, we observe differences in male and female cyclists’ apparent use of bridges, which appear to be strongly related to a commuting function. Studying heuristics of suggested routes over these bridges, we find some evidence to suggest that women may be underrepresented amongst commuting journeys that involve a river crossing because those very journeys are associated with relatively busy and demanding routes. We also find evidence that the nature of frequently cycled journeys involving a river crossing might explain imbalances in the direction of journeys made over the river when we select periods of more discretionary activity – when studying weekend journeys. These findings are nevertheless quite speculative. A number of confounders cannot be easily accounted for within this analysis: the economic geography of the city, spatial interactions between docking stations at particular space-times and the relative availability of transport alternatives. Perhaps most importantly, our analysis assumes that routes suggested by the routing algorithm closely reflect individuals’ actually cycled routes

Characterising group-cycling journeys using interactive graphics

The group-cycling behaviours of over 16,000 members of the London Cycle Hire Scheme (LCHS), a large public bikeshare system, are identified and analysed. Group journeys are defined as trips made by two or more cyclists together in space and time. Detailed insights into group-cycling behaviour are generated using specifically designed visualization software. We find that in many respects group-cycle journeys fit an expected pattern of discretionary activity: group journeys are more likely at weekends, late evenings and lunchtimes; they generally take place within more pleasant parts of the city; and between individuals apparently known to each other. A separate set of group activity is found, however, that coincides with commuting peaks and that appears to be imposed onto LCHS users by the scheme's design. Studying the characteristics of individuals making group journeys, we identify a group of less experienced LCHS cyclists that appear to make more spatially extensive journeys than they would do normally while cycling with others; and that female cyclists are more likely to make late evening journeys when cycling in groups. For 20% of group cyclists, the first journey ever made through the LCHS was a group journey; this is particularly surprising since just 9% of all group cyclists' journeys are group journeys. Moreover, we find that women are very significantly (p<0.001) overrepresented amongst these `first time group cyclists'. Studying the bikeshare cyclists, or bikeshare `friends', that individuals make `first time group journeys' with, we find a significantly high incidence (p<0.001) of group journeys being made with friends of the opposite gender, and for a very large proportion (55%) of members these first ever journeys are made with a friend that shares the same postcode. A substantial insight, then, is that group cycling appears to be a means through which early LCHS usage is initiated

Moving beyond sequential design: Reflections on a rich multi-channel approach to data visualization

We reflect on a four-year engagement with transport authorities and others involving a large dataset describing the use of a public bicycle-sharing scheme. We describe the role visualization of these data played in fostering engagement with policy makers, transport operators, the transport research community, the museum and gallery sector and the general public. We identify each of these as ‘channels’ – evolving relationships between producers and consumers of visualization – where traditional roles of the visualization expert and domain expert are blurred. In each case, we identify the different design decisions that were required to support each of these channels and the role played by the visualization process. Using chauffeured interaction with a flexible visual analytics system we demonstrate how insight was gained by policy makers into gendered spatio-temporal cycle behaviors, how this led to further insight into workplace commuting activity, group cycling behavior and explanations for street navigation choice. We demonstrate how this supported, and was supported by, the seemingly unrelated development of narrative-driven visualization via TEDx, of the creation and the setting of an art installation and the curating of digital and physical artefacts. We assert that existing models of visualization design, of tool/technique development and of insight generation do not adequately capture the richness of parallel engagement via these multiple channels of communication. We argue that developing multiple channels in parallel opens up opportunities for visualization design and analysis by building trust and authority and supporting creativity. This rich, non-sequential approach to visualization design is likely to foster serendipity, deepen insight and increase impact

Couplerlib: a metadata-driven library for the integration of multiple models of higher and lower trophic level marine systems with inexact functional group matching

End-to-end modelling is a rapidly developing strategy for modelling in marine systems science and management. However, problems remain in the area of data matching and sub-model compatibility. A mechanism and novel interfacing system (Couplerlib) is presented whereby a physical–biogeochemical model (General Ocean Turbulence Model–European Regional Seas Ecosystem Model, GOTM–ERSEM) that predicts dynamics of the lower trophic level (LTL) organisms in marine ecosystems is coupled to a dynamic ecosystem model (Ecosim), which predicts food-web interactions among higher trophic level (HTL) organisms. Coupling is achieved by means of a bespoke interface, which handles the system incompatibilities between the models and a more generic Couplerlib library, which uses metadata descriptions in extensible mark-up language (XML) to marshal data between groups, paying attention to functional group mappings and compatibility of units between models. In addition, within Couplerlib, models can be coupled across networks by means of socket mechanisms. As a demonstration of this approach, a food-web model (Ecopath with Ecosim, EwE) and a physical–biogeochemical model (GOTM–ERSEM) representing the North Sea ecosystem were joined with Couplerlib. The output from GOTM–ERSEM varies between years, depending on oceanographic and meteorological conditions. Although inter-annual variability was clearly present, there was always the tendency for an annual cycle consisting of a peak of diatoms in spring, followed by (less nutritious) flagellates and dinoflagellates through the summer, resulting in an early summer peak in the mesozooplankton biomass. Pelagic productivity, predicted by the LTL model, was highly seasonal with little winter food for the higher trophic levels. The Ecosim model was originally based on the assumption of constant annual inputs of energy and, consequently, when coupled, pelagic species suffered population losses over the winter months. By contrast, benthic populations were more stable (although the benthic linkage modelled was purely at the detritus level, so this stability reflects the stability of the Ecosim model). The coupled model was used to examine long-term effects of environmental change, and showed the system to be nutrient limited and relatively unaffected by forecast climate change, especially in the benthos. The stability of an Ecosim formulation for large higher tropic level food webs is discussed and it is concluded that this kind of coupled model formulation is better for examining the effects of long-term environmental change than short-term perturbations

Stormwater sand filters in water-sensitive urban design

This paper investigates the suitability of sand filters for harvesting and treating stormwater for non-potable reuse purposes. A stormwater sand filtration device was constructed in a small urban catchment in Sydney, Australia. A sand filter is typically used in water-sensitive urban design (WSUD) as a component of a treatment train to remove pollution from stormwater before discharge to receiving waters, to groundwater or for collection and reuse. This paper describes an 18 month field study undertaken to determine the effectiveness and pollutant removal efficiency of a sand filter, and the differences in the pollutant removal efficiency of two grades of sand. A comparison of pollutant removal with previous literature on sand filters showed similar efficiencies but nutrient removal was higher than expected. A further unexpected result was that the coarse filter media performed as well as the fine media for most pollutant types and was superior in suspended solids removal. Improved modelling equations for predicting suspended solids and total phosphorus removal in sand filters are also presented in this paper

‘Follow the Moon’ Development: Writing a Systematic Literature Review on Global Software Engineering Education

This presentation reflects on method and practice in Computer Science Education Research, through introducing the process of conducting a Systematic Literature Review. While Systematic Literature Reviews are an established research method within the Software Engineering discipline, they are a relatively unfamiliar research approach within Computer Science Education. Yet research disciplines can be strengthened by borrowing and adapting methods from other fields. I reflect on the rationale and underlying philosophy behind Systematic Reviews, and the implications for conducting a rigorous study and the quality of the resulting outputs. This chronicle of the journey of an ITiCSE working group, outlines the process we adopted and reflects on the methodological and logistical challenges we had to overcome in producing a review titled Challenges and Recommendations for the Design and Conduct of Global Software Engineering Courses. I conclude by discussing how systematic literature reviews can be adapted to an undergraduate teaching setting

Dynamic Design Documents for supporting applied visualization

A common characteristic of applied visualization is collaboration between visualization researcher and domain expert – where the vi- sualization researcher attempts to assimilate sufficient detail around data, task and requirements to design a visualization tool that is manifestly useful. We report on a method for enabling such a col- laboration that can be used throughout the design process to gather and develop requirements and continually evaluate and support iter- ative design. We do so using highly interactive web-pages that we term dynamic design documents. Applied during a four-year visual data analysis project for crime research, these documents enabled a series of data mappings to be explored by our collaborators (crime analysts) remotely – in a flexible and continuous way. We argue that they engendered a level of engagement that is qualitatively dis- tinct from more traditional methods of feedback elicitation, offered a solution to limited and intermittent contact between analyst and visualization researcher and speculate that they provided a means of partially addressing certain intractable deficiencies, such as so- cial desirability-bias, that are common to evaluation in applied data visualization

Supporting crime analysis through visual design

We describe and discuss a visual analysis prototype to support volume crime analysis, a form of exploratory data analysis that aims to identify and describe patterns of criminality using historical and recent crime reports. Analysis requirements are relatively familiar: analysts wish to identify, define and compare sets of crime reports across multiple attributes (space, time and description). A challenge particular to the domain, identified through workshops with Police analysts in Belgium and the UK, is in developing exploratory data analysis software that offers some sophistication in data selection, aggregation and comparison, but with interaction techniques and representations that can be easily understood, navigated and communicated. In light of ongoing discussion with Police analysts, we propose four visual design and interaction maxims that relate to this challenge and discuss an early visual analysis prototype that we hope conforms to these maxims