Sorting Out Cities
Dietmar Offenhuber, Northeastern University
Ars Electronica Futurelab
Animation for the Miraikan Museum, Odaiba, Tokyo
Geo-cosmos at the Miraikan Museum
The sequence starts with a bar-chart
wrapped around the globe that shows how
the land mass is distributed: Ice and desert;
cities; grassland, cropland and savanna;
forests and wetlands. The bar chart
transforms into a map of the earth, showing
how these portions are distributed around the
earth, then moves back into the bar chart. At
the end of the sequence, only the cities
cluster remains and turns into a yellow
circle.Cities are highlighted in yellow.
Cities occupy 3% of the earth’s land
surface. If all urban areas would be
combined in one large city, it would be
slightly larger than the size of Europe,
or about half the size of Brazil.
MODIS 500-m map of global urban extent — Center for Sustainability and the Global
Environment (SAGE), University of Wisconsin-Madison h"p://sage.wisc.edu/people/schneider/
Schneider, A., M. A. Friedl and D. Potere (2009) A new map of global urban extent from MODIS
Le2ers, volume 4, article 044003.
Center for International Earth Science Information Network - CIESIN - Columbia University,
International Food Policy Research Institute - IFPRI, The World Bank, and Centro Internacional de
Agricultura Tropical - CIAT. 2011. Global Rural-Urban Mapping Project, Version 1 (GRUMPv1):
Urban Extents Grid. Palisades, NY: NASA Socioeconomic Data and Applications Center
Balk, D.L., U. Deichmann, G. Yetman, F. Pozzi, S. I. Hay, and A. Nelson. 2006. Determining
Global Population Distribution: Methods, Applications and Data. Advances in Parasitology
The dataset used in the animation is a composite of both data sources, downsampled (nearest
neighbor) to a grid resolution of 500x250.
Two clusters of moving dots appear,
representing the part of the global
population that lives in urban and rural
areas. After a while, the two populations
form a global population map made of dots
of different diameters, representing the
number of people who live in the respective
53% of the global population lives in cities;
the city cluster is slightly larger than the rural
cluster. We also see (in the map, but
especially in the histogram), that more than
half of the global population lives in Southeast
Center for International Earth Science Information Network - CIESIN - Columbia
University. 2014. Gridded Population of the World, Version 4 (GPWv4):
Population Count. Palisades, NY: NASA Socioeconomic Data and Applications
Center (SEDAC). h"p://sedac.ciesin.columbia.edu/data/set/gpw-‐v4-‐populaMon-‐count.
“Cities are located in different climate zones”
The section starts with an animation of the
monthly precipitation over the land mass. The
rainfall animation blends into a map of the
global water footprint, overlaid over the
population map. The relevant water footprint
index here is the amount of fresh water used
in production (including agriculture and
We see that more cities are in relatively
moderate climates. We see that in the
western part of the world, more water is used
in production relative to the population
density compared to the rest of the world.
GPCC Precipitation Normals Version 2010, Global Precipitation Climatology
Centre (GPCC), Deutscher Wetterdienst, Offenbach a. M., Germany
Water footprints of national production (1996-2005). h"p://
Hoekstra, A.Y. and Mekonnen, M.M. (2012) The water footprint of humanity,
Proceedings of the National Academy of Sciences, 109(9): 3232–3237
“90% of the Earth’s land surface can be
reached from a large city within 2 days”
This section shows a map of the world
colored according to the travel time from a
large city to the respective point on the map.
The animation starts with yellow dots (around
urban areas = areas accessible in less than
an hour), blending into red dots (rural areas =
areas accessible in 1-2 hours), and then
ending with black dots (remote areas = areas
accessible in more than 2 days). When the
map is complete, all landmass blends
together and shows a uniform area sorted by
We see that over 90% of the land mass is
accessible in less than two days from a major
city . Remote areas can be located around
the Sahara desert, the Himalaya Mountains,
Greenland and the Amazonian rainforest. In
the densely populated areas, cities can be
reached from most places in minutes rather
Travel time to major cities: A global map of Accessibility, A. Nelson, Global
Environment Monitoring Unit – Joint Research Center (JRC), European
Uchida, H. and Nelson, A. Agglomeration Index: Towards a New Measure of
Urban Concentration. Background paper for the World Bank’s World
Development Report 2009.
“people move between cities”
Starting from our familiar world map,
connecting curves start to emerge between
countries, representing the most signiﬁcant
migration streams (. The width of the curve
corresponds to the number of migrants. The
curves are bundled together rather than
straight connections, to make the hierarchical
nature of connections links easier to read (for
example, the curves from the same
continents and regions are bundled together).
During the past 25 years, Japanese citizens
emigrated to the USA, Brunei, Australia, and
Canada and Brazil. Japan received
immigration from China, South Korea, Brazil,
the Philippines and Peru.
Abel & Sander (2014). Quantifying Global International Migration Flows.
Science, 343 (6178).
Abel (2013). Estimating global migration ﬂow tables using place of birth data.
Demographic Research 28(18):505-546.
The centroid for the ﬂow vectors has been calculated for each country using the
population center of gravity derived from the GRUMP dataset (2).
The 20 largest cities in the year 2030. 10 of
them, including the 4 largest, will be in Asia.
Only 1 of them in Europe, only 2 in North
America. Tokyo remains the world’s largest
An animation introducing the largest urban
clusters in the year 2030, according to
current forecasts by the UN. The animation
concludes with the statement that in the year
2050, two thirds of the world’s population will
live in cities.
United Nations, Department of Economic and Social Affairs (UNDESA),
Population Division special updated estimates of urban population as of October
2011, consistent with World Population Prospects: The 2010 revision and World
Urbanization Prospects: The 2009 revision.