“Calling Abidjan” – estimating population distribution through analysis of mobile phone call data records

Big data, big challenge? Together with Harald Sterly of the University of Cologne I presented a little piece of research in the Extended Spatial Analytics session of the German Geography Congress (Deutscher Kongress für Geographie) in Berlin. The project “Calling Abidjan” that we worked on with Kouassi Dongo of Université de Cocody-Abidjan was started after we successfully applied for participation of the D4D Challenge. According to the initiator Orange telecommunications ‘Data for Development’ is “an innovation challenge open on ICT Big Data for the purposes of societal development”. The project allowed us to work with anonymised mobile phone data from individual call records by Orange in the country of Côte d’Ivoire (Ivory Coast).
We were interested in investigating, what non-computer scientists with a social science and urban planning background can do with such data in a more contextual rather that technically driven way and therefore explored how mobile phone call records can be used to better estimate population distribution.
For our analysis we used anonymised call data records consisting of information about the base station, timestamp, and caller ID produced by the approximately 500.000 Orange Télecom users in the country. There were 1079 base stations at the time the data was generated and we were able to work with data covering 183 days. The dataset consisted of 13GB of raw data which some would perhaps call ‘Big Data’ (though I personally do not like this term for many reasons).
The following two (draft) maps give an insight into the results. The purple circles show the distribution and density of population estimates that we derived using only mobile phone call records dataset. To better see the correlation with what other population data tells us about where people live, we did not only produce a normal land area map (on the left, also displaying some basic idea of the topography in the country) but also showed the data on a gridded population cartogram which we generated from the LandScan population grid, the perhaps most detailed population dataset currently available on a globally consistent high-resolution basis:

Population maps of Ivory Coast / Côte d'Ivoire created using Mobile Phone Call Records
(click for larger version)

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Urbane Veränderungsprozesse in Stadtregionen Deutschlands

This is a German-language poster contribution looking at processes of change in the major urban agglomerations in Germany and novel ways of visualising these using cartogram visualisation techniques. Continue reading

Anthropocene Worlds

The effects of humans on the global environment are perceived to be so significant by some scientists that they argue humans have become a major driving force in environmental change on a par with the forces of nature. It is this rapid impact that has led some geologists to unofficially name (but not, as yet, officially recognise) this very recent period of the earth’s history as the Anthropocene.
Putting criticism and disputes over the geologic validity of this idea aside, the effects of human population and economic development as part of the processes of globalisation influence the natural environment as much as the natural environment previously determined the existence of human life across the globe. One part of our footprint are the major communication and transport infrastructure links that shape the human planet.

Human Worlds - A Map of the Anthropocene
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The Space of Climate Change

Earth Day 2013In the face of unprecendented occurences of extreme weather, loss of species, and pollution, it is clear that climate change is affecting our planet. We cannot afford to wait any longer to act. This quote from the Earth Day 2013 website outlines the theme for this year’s Earth Day campaign which runs under the motto Climate change has many faces.
As the Earth Day campaign points out, the stories of the impact of climate change are extremely diverse: “A man in the Maldives worried about relocating his family as sea levels rise, a farmer in Kansas struggling to make ends meet as prolonged drought ravages the crops, a fisherman on the Niger River whose nets often come up empty, a child in New Jersey who lost her home to a super-storm, a woman in Bangladesh who can’t get fresh water due to more frequent flooding and cyclones.
All these tales have one thing in common: They are a story of our impact on planet Earth, but equally of the impact of a changing planet on human’s lives. Our species has become one that is not just living in the natural environment, but is one factor that changes the environment to a level that no other species did before. This is happening to an extent that geologists discuss whether this can be seen as a new geologic era. Nobel Prize laureate Paul Crutzen started promoting the idea of the so-called Anthropocene, a concept that has now left the scientific world and is increasingly entering the public debate regarding issues of global sustainability and humanity’s impact. Anthropocene.info is a project initiated by the International Geosphere-Biosphere Programme (IGBP) that aims to “to help visualize and better understand humanity’s geographic imprint in recent time.” Not only is it important to find better ways of understanding the complex interrelations of humans and their natural environment, to which visualisation can contribute, but also is it important to create a public understanding of issues relating to the challenges connected to global change.
Here is one example of a more challenging view existing knowledge that demonstrates how changing the view can make us rethink the way our natural environment is shaped. According to research by the US National Office of Oceanic and Atmospheric Research, “[t]he strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the earth’s climate is warmed by increasing levels of greenhouse gases in the atmosphere. Most hurricanes do not reach their maximum potential intensity before weakening over land or cooler ocean regions. However, those storms that do approach their upper-limit intensity are expected to be slightly stronger in the warmer climate due to the higher sea surface temperatures.”
This is relevant due to the impact of more frequent flooding and cyclones on humans mentioned earlier. So where are these spaces where this is relevant. We know from historic records where there are tropical storm tracks, and the emerging pattern on a normal world map may be familiar to some of us (see here). But what if we change the perspective and focus on the actual areas that have the highest density of tropical storm occurrences. Using the records from 1945 to 2008, this intensity can be turned into quantities which are suitable for visualisation using the gridded cartogram technique. The following map shows a gridded cartogram of tropical storm intensity visualised over land based on a 0.25 degree grid. The larger a grid cell, the more tropical storm activity has there been over the past >60 years, indicating where the most affected areas of tropical cyclones (with a sustained wind speed of ver 40 mp/h) has been and how the climate patterns shape the world in a highly relevant issue of the Anthropocene:

Gridded Cartogram / Map of Tropical Storm Intensity
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The Visualisation of Spatial Social Structure: Reflections on Critical Methods

‘(How) do we understand Capitalism? Reflections on critical methods’ was the title of a workshop on critical methods at the University of Manchester (September 13-14th). As the announcement of the workshop states, ‘there is no consensus on what critical social science is, exactly. Largely it is defined as not orthodox economics or positivist social science‘. Continue reading

Global Spaces of Food Production


Global Spaces of Food Production
In the year 2000 there were approximately 15 million square km of cropland and 28 million square km of pasture which are represented in the two main maps. These are equal to 12% respectively 22% of the ice-free land surface. This is according to estimates of a study on the geographic distribution of global agricultural lands by Ramankutty et al (published in Global Biogeochemical Cycles, 2008) who used a methodology of combining agricultural inventory data and satellite-derived land cover data to come to these figures (data can be accessed via Columbia University’s SEDAC). Continue reading