All posts by Carsten

Future megacity-regions and heatwave exposure

We have a new book chapter out, looking into future exposure to 15-day heat waves in the world’s 20 largest megacity-regions under different combinations of SSP, RCP, and urbanisation scenarios. Snippet from the conclusions:

This study presents the results of urban spatial simulations based upon SSPs, which indicate the emergence of extremely large megacity-regions around the world by 2100. These data are then matched with climate data for very warm (> 42°C) 15-day heatwaves for different RCPs. The combination suggests that even under strong global responses to climate change, large populations (1 billion) within these very large cities (1 billion) are projected to be exposed to these conditions in the future and these numbers could double under other development pathways.

Peter J. Marcotullio, Carsten Keßler and Balázs M. Fekete (2020) Future megacity-regions and heatwave exposure. In: Danielle Labbé and André Sorensen, eds.: Handbook of Megacities and Megacity-Regions, pp.309–326. Edward Elgar Publishing, ISBN: 978-1-78897-269.

New Horizon 2020 Project on “Future Migration Scenarios for Europe”

Our group is leading a consortium of 9 partners that has received funding from the European Commission to work on Future Migration Scenarios for Europe for the next 3 years. Here’s the short description from the EU’s CORDIS project database:

The local circumstances play a major role in the migration process, from the decision to migrate through the transit process up to the settlement in the destination countries. Nearly all international migrants move to – generally the largest – cities in destination countries, either directly, or after one or more internal moves. This is also the case across Europe, where population growth in many cities can be largely attributed to an influx of migrants. At the same time, in countries of origin the largest cities often function as gateways to destinations abroad. Many potential migrants in villages and small towns in origin countries first move to these larger cities before leaving their country. Cities, therefore, both in countries of origin and destination, are significant determinants of global migration and small-scale local knowledge on migration is necessary to avoid misleading results associated with the limitations arising from the use of global or national patterns only. FUME will therefore focus on understanding the patterns, motivations and modalities of migration at multiple geographical scales, from international through regional to the local, and on imagining possible futures. FUME will determine 1) the major factors explaining migrant movement patterns by analysing regional and local circumstances that either attract migrants or ‘push’ potential migrants to move, and 2) elaborate how possible future regional socio-demographic, economic and environmental challenges may shape future migrant movement patterns in Europe. FUME will support appropriate planning and policy-making by formulating integrated and coherent visions of how migration to and within Europe might evolve under different scenarios relating to potential demographic, socio-economic, political and environmental challenges.

The project website has more information about the consortium and the goals of the project. Moreover, you are more than welcome to join the open day at our kick-off conference on January 30, 2020 here in Copenhagen.

JOSIS special feature on Geospatial Privacy and Security published

Grant McKenzie, Clio Andris and I have edited a small special feature in the Journal of Spatial Information Systems on Geospatial Privacy and Security, following our workshop under (almost) the same title at GIScience 2018 in Melbourne. The two accepted papers are entitled Privacy, Space and Time: a Survey on Privacy-Preserving Continuous Data Publishing by Manos Katsomallos, Katerina Tzompanaki, Dimitris Kotzinos and Exploring the effectiveness of geomasking techniques for protecting the geoprivacy of Twitter users by Song Gao, Jinmeng Rao, Xinyi Liu, Yuhao Kang, Qunying Huang, Joseph App, plus a short editorial by the three of us.

As always with JOSIS, Open Access and free to read for everyone.

Book chapter on Geospatial Information Infrastructures published

Our chapter on Geospatial Information Infrastructures in Springer’s Open Access Manual of Digital Earth has just been published.

Abstract: Geospatial information infrastructures (GIIs) provide the technological, semantic, organizational and legal structure that allow for the discovery, sharing, and use of geospatial information (GI). In this chapter, we introduce the overall concept and surrounding notions such as geographic information systems (GIS) and spatial data infrastructures (SDI). We outline the history of GIIs in terms of the organizational and technological developments as well as the current state-of-art, and reflect on some of the central challenges and possible future trajectories. We focus on the tension between increased needs for standardization and the ever-accelerating technological changes. We conclude that GIIs evolved as a strong underpinning contribution to implementation of the Digital Earth vision. In the future, these infrastructures are challenged to become flexible and robust enough to absorb and embrace technological transformations and the accompanying societal and organizational implications. With this contribution, we present the reader a comprehensive overview of the field and a solid basis for reflections about future developments.

Reference: Sven Schade, Carlos Granell, Glenn Vancauwenberghe, Carsten Keßler, Danny Vandenbroucke, Ian Masser, Michael Gould (2019) Geospatial Information Infrastructures. In: Huadong Guo, Michael Goodchild, Alessandro Annoni (eds.), Manual of Digital Earth, pp. 161–190. Springer/International Society for Digital Earth. DOI:10.1007/978-981-32-9915-3

Two Papers Accepted for LBS 2019

This is the first time I’ll be attending the Conference on Location Based Services and we have two papers in the program:

Marina Georgati, Carsten Keßler
A 3D Routing Service for Indoor Environments

Preprint PDF

Abstract: Large and complex buildings with substantial numbers of visitors require fast and effective navigation support to help first-time and infrequent guests to easily find their destination and avoid stressful situations. Most existing solutions are based on in-situ localization and routing, therefore requiring expensive indoor positioning infrastructure. In contrast, the objective of this research is the development of a cheap and easily deployable indoor routing service that visitors can use to plan the route to their destination before their visit. It visualizes both the interior space of a building and its users’ individual routing paths in a virtual 3D environment. The proposed solution is entirely based on open source tools and has no installation requirements for the user. Its functionality is demonstrated in a building at the Aalborg University Copenhagen campus. This kind of ex-situ 3D digital navigation promises to help users gain a better understanding of the explored environment, and to improve people’s cognitive spatial maps when combined with animated stimuli and landmarks.

Carsten Keßler, Grant D. McKenzie
Consistency Across Geosocial Media Platforms

Preprint PDF

Abstract: The increasing use of geosocial media in research to draw quantitative and qualitative conclusions about urban environments bears questions about the consistency of the data across the different platforms. This paper therefore presents an initial comparative analysis of data from six different geosocial media platforms (Facebook, Twitter, Google, Foursquare, Flickr, and Instagram) for Washington, D.C., using population and zoning data for reference. We find that there is little consistency between the different platforms at small spatial units and even semantically rich datasets have severe limitations when predicting functional zones in a city. The results show that researchers need to carefully evaluate which platform they can use for a particular study, and that more work is needed to better understand the differences between the different platforms.

Paper accepted for AGILE 2019: Route Optimisation for Winter Maintenance

We have a paper accepted for AGILE 2019 in Limassol:

Nikmal Raghestani and Carsten Keßler (2019)
Route Optimisation for Winter Maintenance (← preprint)

Abstract: In many countries, winter maintenance is a requirement to keep public life going throughout the cold season. This paper investigates the optimization of salt spreading routes in Denmark in terms of service time and cost. It looks at salting as a capacitated arc routing problem and proposes a greedy randomized adaptive search procedure to this end. At the core of the proposed approach is a heuristic algorithm based on simulated annealing that improves the initial route by searching for alternatives within a predefined search space, taking into account a number of constraints and criteria at each iteration of the procedure. The performance of the optimization approach is tested on three different existing service routes, where it is shown to reduce route length by an average of 8.7% and service time by an average of 9.5%.

Silent Shout →

“Our phone is going around the city asking, ‘Are you ‘Home Wi-fi’? Are you ‘Home Wi-fi’?’ Your phone does that one network at a time but it always sends out its MAC address and the name of the network,” Briz continued. “So then it might be like, ‘Hey, it’s me. Here’s my MAC address again. Now I’m looking for ‘Work Wi-fi’, now that cafe I connected to once, now ‘Mom’s House’, and so on.’” The protocol is structured like a Greek tragedy, with recurrent choral interjections and a relentless quest for home.

Many people think that you need GPS to be able to locate a device. This article explains very nicely why WiFi alone is a very capable tracking technology if you are walking around with a smartphone all day – and why this huge privacy issue is very unlikely to go away.

JOSIS Special Issue on Geospatial Privacy & Security

First Call for Papers: Special Issue on Geospatial Privacy & Security in the Journal of Spatial Information Science


Location privacy has been a consistent theme in spatial information science for quite some time. While early work on this topic was primarily focused on theoretical concerns over the exploitation of personal location information, recent advances in mobile technology have spurred renewed interest in this domain. As the ubiquity of these sensor-rich devices, smart homes and cities, and content contributed to geosocial media applications increases, the privacy and security of our personal data has come to the forefront of our social dialog. Citizens today are demonstrating appropriate concerns about data sharing, how their data are being used, and implications of having so much data in the hands of a select few.

Researchers in the spatial sciences offer a unique perspective on the discussion of data privacy and security. As a substantial amount of data are generated with some level of location information, a better understanding of the privacy implications of working with, and securing these data are paramount. Additionally, spatial data supports its own unique set of quantitative and qualitative analysis techniques, many of which may impact the privacy of the data contributor or expose details on how the data was created. Researchers in the geospatial sciences are well situated to explore these numerous aspects (as well as the social, economic, political, etc. lenses) through which location privacy and data security can be framed.

Topics of interest for the special feature include, but are not limited to:

  • Context-aware mobile applications
  • Obfuscation techniques
  • Educational approaches to location privacy
  • Policy implications of personal location information
  • Role of location in personal relationship development
  • Geosocial media implications
  • Credibility, trust, and expertise related to location information
  • Tools and systems for preserving or securing private information
  • Techniques for sharing private location information
  • Methods for securing location information
  • Place-based data privacy
  • Individual vs. group privacy preservation
  • Gamification techniques
  • Next-generation location-based services
  • Geofencing
  • Marketplaces for location data
  • Legal aspects of geoprivacy
  • Connections between location data and other kinds of personally identifiable information

Important Dates

Paper Submission: January 31, 2019
Paper Notification: April 30, 2019

Submissions of the following types will be considered:

  • Research papers on original research results
  • Surveys on the state of research in the outlined areas
  • System and Application reports on research enabling tools, lessons learned from applications, user interaction & interfaces

Guest Editors

Grant McKenzie, McGill University, Quebec, Canada
Carsten Keßler, Aalborg University, Copenhagen, Denmark
Clio Andris, Penn State University, State College, USA

Feel free to reach out to one of the guest editors with any questions pertaining to this special issue.

Location Privacy Panel @ GI_Forum 2018

I’ll be heading down to Salzburg this week to moderate the closing session at GI_Forum 2018, which will be a panel discussion on location privacy. I’m looking forward to an interesting discussion with the panelists:

  • Francis Harvey, Leibnitz-Institut für Länderkunde, Germany
  • Jochen Höfferer, STADT:SALZBURG, Head of Marketing & Digitization
  • Dietmar Jahnel, Department of Public Law, University of Salzburg
  • Bernd Resch, Department of Geoinformatics – Z_GIS, University of Salzburg

Abstract: Paying with a credit card, swiping the monthly pass at the subway station, or recording workouts with a fitness tracker all contribute to a detailed picture of our movement patterns and associated activities. Moreover, most of us constantly carry a mobile phone, which produces an even more detailed and continuous personal-level location history. This panel will discuss the implications that these developments have on our location privacy. Is it worth giving up on privacy for the gained convenience? Is my current location – in public – a matter of privacy? Do we still even have a chance to escape this seemingly voluntary surveillance machine? And who may gain access to our location data? The panel will discuss these questions based on a series of short opening statements from the panelists, followed by a discussion bringing together the legal, technological, and ethical dimensions of location privacy.