Participatory data physicalisation (PDP) is recognised for its potential to support data-driven decisions among stakeholders who collaboratively construct physical elements into commonly insightful visualisations. Like all participatory processes, PDP is however influenced by underlying power dynamics that might lead to issues regarding extractive participation, marginalisation, or exclusion, among others. We first identified the decisions behind these power dynamics by developing an ontology that synthesises critical theoretical insights from both visualisation and participatory design research, which were then systematically applied unto a representative corpus of 23 PDP artefacts. By revealing how shared decisions are guided by different agendas, this paper presents three contributions: 1) a cross-disciplinary ontology that facilitates the systematic analysis of existing and novel PDP artefacts and processes; which leads to 2) six PDP agendas that reflect the key power dynamics in current PDP practice, revealing the diversity of orientations towards stakeholder participation in PDP practice; and 3) a set of critical considerations that should guide how power dynamics can be balanced, such as by reflecting on how issues are represented, data is contextualised, participants express their meanings, and how participants can dissent with flexible artefact construction. Consequently, this study advances a feminist research agenda by guiding researchers and practitioners in openly reflecting on and sharing responsibilities in data physicalisation and participatory data visualisation.

Organisations require diverse technological infrastructures to create value from data. Because these infrastructures are often haphazardly developed, they cause frictions between the socio-technical agencies of the involved stakeholders. Datopolis is a role-playing game consisting of cards, tiles and tokens that was specifically designed to support such stakeholders to experience, understand and reflect on how data infrastructures should be developed and maintained. Although the game has reached more than 20 organisations in 8 different countries since its original release 8 years ago, little is known about how its resources and rules actually elicit critical reflection among its players. By conducting a retrospective qualitative study consisting of 27 interviews with stakeholders, we uncovered that the prototypical role-playing narrative drives critical reflection through 3 facilitation approaches and 3 play strategies that are anchored in organisational contexts shared among players. We are thus able to present three contributions: 1) a retrospective study grounded in interviews with actual stakeholders being affected by the game; 2) an overview of play strategies and facilitation approaches that enacted the infrastructuring processes through role-play; and 3) critical considerations to operationalise how role-play supports learning, situated in real-world contexts and shaped by facilitation. This study calls for a critical examination of the role of interpretation during learning activities to empower stakeholders in reclaiming control over organisational practices.

This paper aims to show the usefulness of GIS and point pattern techniques for defining road-accident black zones within urban agglomerations. The location of road accidents is based on dynamic segmentation, address geocoding and intersection identification. One-dimensional (line) and two-dimensional (area) clustering techniques for road accidents are compared. Advantages and drawbacks are discussed in relation to network and traffic characteristics. Linear spatial clustering techniques appear to be better suited when traffic flows can be clearly identified along certain routes. For dense road networks with diffuse traffic patterns, two-dimensional techniques make it possible to identify accident-prone areas. The operationality of the techniques is illustrated by showing the impact of traffic-calming measures on the location and type of accidents in one Belgian town (Mechelen).