Origin–destination flow maps are a popular option to visualize connections between different spatial locations, where specific routes between the origin and destination are unknown or irrelevant. Visualizing origin–destination flows is challenging mainly due to visual clutter which appears quickly as data sets grow. Clutter reduction techniques are intensively explored in the information visualization and cartography domains. However, current automatic techniques for origin–destination flow visualization, such as edge bundling, are not available in geographic information systems which are widely used to visualize spatial data, such as origin–destination flows. In this article, we explore the applicability of edge bundling to spatial data sets and necessary adaptations under the constraints inherent to platform-independent geographic information system scripting environments. We propose (1) a new clustering technique for origin–destination flows that provides within-cluster consistency to speed up computations, (2) an edge bundling approach based on force-directed edge bundling employing matrix computations, (3) a new technique to determine the local strength of a bundle leveraging spatial indexes, and (4) a geographic information system–based technique to spatially offset bundles describing different flow directions. Finally, we evaluate our method by applying it to origin–destination flow data sets with a wide variety of different data characteristics.

Studying the so-called refugee crisis in Germany, this article asks about the effectiveness of crisis management by a large number of local administrations, each acting upon the same crisis impulse of a high number of asylum seekers who entered the country in 2015 and 2016. Instead of theorizing the exact administrative design features fit for an effective crisis response, the focus is on the ability of administrations to adjust. We conceptualize such shifts in administrative practices as informal and temporary (latent) deviations from routine action along two dimensions of organizational behavior typically dominant in private and nonprofit sector organizations, respectively: internal flexibility and citizen participation (hybridity). Novel survey data from 235 out of 401 German district authorities are reported. We test the effects of different forms of latent hybridization on administrative effectiveness using regression modeling. Findings indicate that changes in administrative practices towards more flexible and participatory action had a positive impact on self-reported crisis management effectiveness. The effect of flexible action was especially pronounced in districts that were allocated higher shares of asylum seekers. These findings advance theory on crisis management and bottom-up implementation, highlighting the ability of local agencies to shift practices as a key explanatory factor for effective administrative action in exceptional situations.

Affluence and vulnerability are often seen as opposite sides of a coin—with affluence generally understood as reducing forms of vulnerability through increased resilience and adaptive capacity. However, in the context of climate change and an increase in associated hazards and disasters, we suggest the need to re-examine this dynamic relationship—a complex association we define here as the Affluence–Vulnerability Interface (AVI). We review research in different national contexts to show how a more nuanced understanding of the AVI can (a) problematize the notion that increasing material affluence necessarily has a mitigating influence on social vulnerability, (b) extend our analysis of social vulnerability beyond low-income regions to include affluent contexts and (c) improve our understanding of how psychosocial characteristics influence people’s vulnerability. Finally, we briefly outline three methodological approaches that we believe will assist future engagement with the AVI.

. Tim's research has focused on risk and decision making under uncertainty, particularly in relation to individual, community and organizational preparation and response to environmental risk. His most recent work has included foresighting research on natural resource security in Australia, as well as exploring new mechanisms for risk communication with respect to natural hazards like wildfire. Florian Roth is a researcher at the Center for Security Studies. He studied Political Science, History, Arts and Media at the University of Konstanz. His research interests include security risk management, risk communication as well as armed conflicts and peace operations. AbstractToday the majority of the globe's inhabitants live in urban areas, and according to all prognoses, cities will continue to grow in the coming decades. Global cities are also becoming increasingly connected as a result of economic, political, cultural and demographic globalization. In the context of urban security management, the growing complexity these connections bring may present a double-edged sword: global cities can be both the most secure and the most dangerous places to be when disaster strikes. Developing appropriate mechanisms to prepare for and cope with complex crises in cities will, in the future, be a key aspect of security policy-making. In this article we explore current trends in research and practice concerning the management of disasters in eight global cities, particularly focusing on aspects of preparedness, response, urban resilience and cooperation. The results of the study indicate that cities must improve the capacity to predict new or unforeseen risk by diversifying capabilities for risk assessment and improving inter-agency collaborations. In addition, cities must adopt new approaches to disaster management that are sufficiently flexible to adapt to a changing risk environment and to safeguard urban security.