During the last years the availability of spatial data has rapidly developed, in particular through the diffusion of social networks, Web 2.0 platforms and availability of suitable sensor technologies. A clear indication of this trend is the participation of users to the production of so called “Volunteered Geographic Information”, shortly VGI, due to the vast use of smartphones and mobile devices. In the current information society era, these data provide a variety of applications, not only for the solution of societal challenges such as in environment, health or transport fields, but also for the development of commercial products and services.

The core question of this Priority Programme is how visualisation methods can contribute to the utilisation of VGI and support the interaction of users involved. Research questions span from the extraction of spatial information, to the visual analysis and knowledge presentation, taking into account the social context while collecting and using VGI. The heterogeneity and the limited semantic structure of user generated spatial data represent a major challenge. Methods already available for data analysis and integration, may only partially be of help, as they have been developed for more structured geographic data, and in the case of VGI a spatial, temporal and thematic reference is often only implicitly given. Therefore, an important task is the development of processing methods, which support different interpretations and derivation of varying abstraction degrees applicable to sensor data streams as well as specific user generated data. Similarly, the development of methods for textual analysis and computational linguistics for space-time-related question plays a relevant role. These methods encompass for example the extraction of toponyms for an automatic georeferencing with resolution of ambiguities; the thematic categorisation and topic modeling in conjunction with spatial confinement, and opinion, ratings or sentiment analysis. Particularly significant when dealing with VGI are the concepts of quality and trust. The usual quality measures such as completeness, consistency and accuracy, must be adapted for this type of data (e.g. a high temporal accuracy may be integrated with a lower thematic accuracy.

Closely related to this is the development of visualisation methods for displaying meta-information. As a matter of fact, when dealing with the cartographic representation of uncertainty, it is necessary also to visualise the variability, which may be expressed in user-generated data. The programme will give a particular emphasis to the development of methods that allow the representation and visualisation of metaphors to reflect the characteristics of user-generated data. This comprises methods for the real-time analysis (stream data) and visual exploration in space and time, and the integration of different media types, e.g. text, pictures, videos. To this aim, significantly challenging will be the ability to deal with large amount of data. To make both detailed and summary information available, automatic abstraction methods in addition to interactive selection and filter methods are required. Geo-visual analysis needs interaction methods that take into account both the cognitive abilities of people and the context of usage. The aim is to involve different user groups in the information flow by means of VGI and let them participate in the decision-making process.

In the area of Social Computing the intersection between social behaviour and computer systems should be explored during the collective acquisition, processing and use of VGI. This includes, for example, to take into account different sources and usage contexts, the evaluation of subjective information, as well as the compliance with data protection and privacy. Methods coming from social and intelligent computer systems, and applied for space-time-related issues, would need a further development, including among others collaborative filtering, agent-based prediction model, reputation systems, or use of games for verification (gamification).

In this Priority Programme fields like information extraction from VGI, analysis of social context factors, interactive analysis and visual representation should not be separately treated. Rather, their interactions and dependencies have to be considered both at methodological and application level (e.g. implementation and workflow must be portable to different contexts). Each project aims at involving different user groups in the development phase as well as in the empirical verification. A great opportunity of the programme also consists in the use of voluntary participations, raising in this way the awareness support, and thus leading to sustainable development and problem solving.