Visualization of Satellite Data Availability: TerraSAR-X and TanDEM-X Running Against Time

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The currency of geodata is an important factor for many advanced geospatial applications. Examples for this are security questions in the control of international borders and coastal areas, or up-to-date information following natural hazards. Here a near real time availability of geoinformation is of high value. A wide range of commercial satellites providing near real time information are available. Satellites with active sensors, such as Synthetic Aperture Radar (SAR) systems, can deliver such information even at night and in areas with cloud coverage.

Cartogram visualisation of the TerraSAR-X and TanDEM-X latency
(click for larger version)

The German SAR satellite mission with the TerraSAR-X and TanDEM-X satellites provides coverage of every location on earth within 1-3 days. The acquired data can be made available for processing within hours or in certain cases even minutes. Continue reading

China’s gender gap: Man-made problems?

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CHINET“In recent decades, the world has witnessed the enormous economic, social, cultural and political development of China. As the most populous country in the world, China’s transition process influences directly one fifth of the world’s population and indirectly almost all the rest of the world. Chinese economic activities cover the whole globe, Chinese living overseas constitute the largest diaspora, and China’s political and economic influence is significant. On the other hand, China and its government face many challenges, as Chinese society as well as the environment are affected by these massive processes.” These challenges were the theme of a Conference on the Socio-Economic Transition of China at Palacký University in Olomouc (Czech Republic) where the opportunities and potential threats for China are discussed from an interdisciplinary perspective organized by the CHINET (Forging a scientific team and international networking in the field of Chinese Studies) project.
Part of that was an invited contribution which I prepared in collaboration with Adam Horálek of Palacký University. Our talk titled ‘Mapping Perspectives of Changing China’ presented a global as well as national context to the topic, framing China’s socio-economic place in the globalised world and highlighting some of the trends that started transforming the Chinese society considerably over the past three decades. While the most recent Census is not yet available in larger detail, we focussed on an analysis of some key aspects of the previous Census in more detail (and also discussed the quality and reliability of data from official statistics there).
The following map showing the gender gap was part of our slides (see below) and stands for one of the demographic challenges and existing tensions in the contemporary society. These are not only characterized by the changing age structures (with very distinct geographic patterns of ageing populations), but also by the considerable imbalance between the male and female population in most parts of the country. According to the most recent 2010 Census, this was at 1.18 males per female, and thus increased to the already high ratio that was stated 10 years before. In some regions, there are now over 130 men for 100 woman, with the fear (and sometimes reality), “that the excess will lead to increased sexual violence, general crime and social instability” (quoted from the Guardian). It is very much a man-made problem as in the early 1980s the ratio was at 108:100 and therefore only slightly above the natural rate, after which the 1979 introduced one child policy started having an effect that we see in its full extent today. This map, showing the sex ratio on an equal population projection (a gridded cartogram transformation where each grid cell is resized according to the total number of people in an area). It reveals, that the surplus of men is common throughout the country, while the opposite (a considerable surplus of women) is true for very few of the populated spaces in China (such as in the Shenzhen area of the Pearl River Delta where female migrants are the majority of workers under precarious employment conditions).
The authorities appear to become aware of the emerging problems, and according to the Guardian article, China’s “new Five Year Plan sets an ambitious target of cutting the ratio to 112 or 113 by 2016″. For the time being, the pattern in this map remains prevalent and puts pressure on a society that is feeling the full impact of China’s transformation to a new global player over the past decades.

Male to Female Sex Ratio in China
(click for larger version)

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Londonmapper goes #geomob: Visualising London with Cartograms

Today I was invited to give a presentation at the quarterly #geomob meetup for location based service developers which this time took place at the Google Campus in East London. In my talk I gave a short preview of the Londonmapper project that I am working on with my colleagues and the Trust for London. Unfortunately technology played some tricks on us and some of the animated bits and content did not show up during the presentation, so that I promised to put these on my blog alongside the slides of the talk. Here we go…
This first animation was an introduction into showing how cartograms work in general. I used a gridded population cartogram animation for Great Britain which I created years ago, demonstrating the approach of using a gridded cartogram to allow other layers being used in the transformed map. The following map (which is rather drafty as it was only a conceptual exercise) shows Great Britain overlaid with a topographic layer indicating the land elevation, as well as some key rivers and a selection of the motorway network. During the animation this map transforms from a conventional land area map into a gridded population cartogram where each grid cell is resized according to the total number of people living there. While the grid cells change their size, the other geographic layers are changed accordingly, so that the final cartogram shows these layers in relation to the population distribution, i.e. at which elevations do people live and how are people linked to major roads. The animation also demonstrates the magnifying lens effect in the most densely populated areas. Motorways and even the curvy shapes of the river Thames become visible now which at such a scale cannot be seen from a normal map. Gridded cartograms hence help to highlight details in these areas that are most relevant in the transformed space.

Gridded Cartogram Animation of Great Britain
(click for larger version)

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Into the big wide open: Think (twice) before you map!

A little bit from my archives which I never got around putting online before…here it comes: Last September I was invited to do a keynote at FOSS4G, OSGeo’s Global Conference for Open Source Geospatial Software. The event is the annual gathering of Open Source Geospatial Developers, Users and Leaders and was held at Nottingham’s new East Midlands Conference Centre, 17th to 21st September. The conference motto was ‘Geo for all’ because, as the organisers explain, “many people who work with geo software and maps find themselves becoming passionate advocates for the power of geography to make a difference: in government, business, travel, environment, crime reduction, social justice and communications to name just a few domains. Open Source Geo software makes this possible.
So how does a geographer, working with geospatial software but being less so a developer, address a huge crowd of people who are little reluctant to see themselves as geeks and nerds? Instead of pretending to be as clever as most of the audience I took a slightly different stance, trying to bridge the gap between those on the programming side and those on the applied side – two groups which sadly rarely speak to each other. Traditional cartographers often see their field of work undermined (and threatened) by computerised methods to generate mapping products, while coders very often find the obsession with minute detail and ‘artisan’ cartography annoying. If the two worlds would come a bit closer together, and both sides speak a bit more with each other, the world of cartography and geospatial visualisations could benefit so much more. Addressing a more technical audience, I concluded that we should all think a little bit more before we start mapping, and that we should give a good mapping project a little bit more time than we often do these days – but more importantly of course: We should never stop mapping. These are the slides of my talk, of course including many maps:

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Where the Wild Spaces Are: Un planeta salvaje

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Make the world a wilder place | Por un planeta más salvaje
Where the Wild Spaces Are - WILD10 Conference 2013, Salamanca, Spain

Wilderness and remote areas are a diverse element in the patchwork of spaces that form the land surface of our planet. Only very small amounts of people are living in sparsely populated areas, which is an expression of the strong organisation of human societies to maximise those living in close relative proximity. More than half of the world’s population now lives in areas categorised as cities, and although more than 95% of the world’s population live in approximately only 10% of the land area, the remaining 90% of space on land are far from being uniform remote or even wild areas.
There are very different ways of how the un-built area that still makes the largest share of land can be understood in terms of being under influence and in reach of human civilization. Only 15% of people in rich countries live more than an hour of travel time from a city (of at least 50,000 people), while the same applies to 65% of people living in the poor countries of the world. This paper demonstrates a different approach to visualising and understanding these loneliest places on the planet by using a technique called a gridded cartogram transformation. The following map shows a gridded cartogram visualising the relative distance of areas to the majority of people. The maps derived from the distorted grid show the physical space transformed according to the absolute travel time that is needed to reach the nearest major city by land transport averaged over the area of a grid cell, resulting in a map that gives the remotest places most space and provides a unique new perspective on the spatial dimension of remoteness:


(click for larger version – high resolution PDF)

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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