Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Earth Institute announces results of global mapping project

09.03.2005


GRUMP mapping project finds urban areas increasing in surprising ways



The majority of the world’s population will soon live in urban rather than rural areas. Adding a spatial dimension to population estimates, a new study finds that as much as three percent of the Earth’s land area has already been urbanized, which is double previous estimates.

This new data collection, known as the Global Rural Urban Mapping Project, or GRUMP, has provided the basis for a number of important insights not previously known. This project is led by the Center for International Earth Science Information Network (CIESIN), part of the Earth Institute.


The following are a few key insights from GRUMP:

  • GRUMP shows that 20% of the world’s urban settlements have populations below 500,000. This is an important finding considering that the UN Population Division only reports on urban settlements of 500,000 inhabitants or more.
  • GRUMP data indicate that roughly 3% of the Earth’s surface is occupied by urban areas, an increase of at least 50% over previous estimates that urban areas occupied 1-2% of the Earth’s total land area.
  • Coastal environments have much higher concentrations of urban land area (10%) and urban populations (65%) than other ecosystems.
  • Far fewer Asian and African urban residents live in coastal and cultivated areas than residents of the Americas, Europe and Oceania, however, population densities in coastal cities of Asia and Africa are much greater than those on other continents.
  • GRUMP shows that approximately 7% of urban dwellers now reside in the world’s largest mega-cities, whereas experts had previously estimated this number to be around 4%.
  • GRUMP has identified about 75,000 distinct settlements worldwide, but only 24,000 urban areas—the result of many agglomerated urban settlements

“The GRUMP datasets will allow us to rethink trends in urbanization and the relationship between population, ecosystems and land use,” explained Dr. Deborah Balk, a demographer at CIESIN and the principal investigator of GRUMP. “GRUMP shows us that the urban experience is not uniform, that city-size matters, and city distribution matters. Coastal areas are more urban than other ecosystems, for example, and even rural populations in coastal ecosystems are much denser than in other rural areas.”

This study has resulted in the construction of a suite of products constituting the first detailed and systematic data sets on urban population distribution and the extents of human settlements across the globe.

Although population census and satellite data have been available for some time, until now minimal effort had been made to combine these two kinds of information to capture the geographic boundaries of human settlements.

The GRUMP data collection consists of three individual databases that build upon population datasets mostly from national statistical offices, satellite data and other representations of settlements. GRUMP Human Settlements is a global database of cities and towns of 1,000 persons or more, each represented as a point, and includes information on population sizes, longitude and latitude coordinates, and data sources. Populations were estimated for 1990, 1995 and 2000. The GRUMP Urban ExtentMask is the first systematic global-scale attempt to portray the boundaries of urban areas with defined populations of 5,000 and larger. The GRUMP Population Grid represents the distribution of human population across the globe, accounting for urban population concentration more precisely than previous efforts. It allows for inferences about urban versus rural populations, and cities of different sizes, when used in combination with the Urban Extent Mask.

In contrast, prior data sets such as those from the United Nations or the Digital Chart of the World indicated either the population size or extent of urban areas, but not both.

“For us, knowing more about the number and distribution of rural populations is critical,” said Stanley Wood, head of the Spatial Analysis Research Group at the International Food Policy Research Institute (IFPRI) that supported and collaborated on GRUMP. “Past spatial population datasets have confounded urban and rural populations, but the better we can distinguish patterns of rural population, farming and use of natural resources, the better placed we are to address the major challenges of rural development and poverty alleviation. GRUMP is an important step in the right direction.”

GRUMP delineates urban boundaries across the planet ranging in size from 1 km2 to the largest of urban extents, Tokyo, which includes more than 500 connected settlements and is the largest urbanized area in the world at 30,000 km2. “The night-time lights satellite, the [primary technology used to detect] urban extents, tends to overestimate the geographic size of highly-electrified cities, but for those cities, we have much more detailed sub-city population data to supplement the extent information,” said Balk. GRUMP has shown that in the year 2000, there were 24,000 urban areas across the globe with 5,000 residents or more. “We know that this is an undercount, because the poorest countries have urban areas that were either hard to detect with the satellite or have weak census-taking. This method is novel and a huge improvement over previous databases. It’s not perfect, but it’s an important achievement,” Balk said.

“Eventually, GRUMP data should revolutionize the way population figures are debated and discussed,” said Dr. Gordon McGranahan, Director of the Human Settlements Programme at the International Institute for Environment and Development. “The GRUMP presentation of data, particularly if combined with population estimates by location, is so much more amenable to up- and down-scaling and local verification than conventional tables.”

GRUMP data took four years to compile. It drew on years of investment from the Gridded Population of the World (GPW) project in which population counts are converted from irregularly and administratively defined census units to a uniform latitude-longitude grid.

The GRUMP datasets, as well as the newest release (version 3) of GPW, may be accessed through the NASA Socioeconomic Data and Applications Center (SEDAC), operated by CIESIN, at http://beta.sedac.ciesin.columbia.edu/gpw/

GRUMP and GPW datasets and map collections are distributed free of charge.

GRUMP is a collaborative project with partners from IFPRI, the World Bank and the International Center for Tropical Agriculture. Primary financial support was provided by the US National Aeronautics and Space Administration, IFPRI, and the World Conservation Monitoring Center for the Millennium Ecosystem Assessment (www.maweb.org).

The Center for International Earth Science Information Network (CIESIN), a member of the Earth Institute at Columbia University, works at the intersection of the social, natural, and information sciences. Scientists at CIESIN specialize in online data and information management, spatial data integration and training, and interdisciplinary research related to human interactions in the environment. CIESIN researchers seek to provide data that informs scientific, public and private decision-makers worldwide. For more information, visit www.earth.columbia.edu

The Earth Institute at Columbia University is the world’s leading academic center for the integrated study of Earth, its environment and society. The Earth Institute builds upon excellence in the core disciplines — earth sciences, biological sciences, engineering sciences, social sciences and health sciences — and stresses cross-disciplinary approaches to complex problems. Through research, training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world’s poor. For more information, visit www.earth.columbia.edu.

Clare Oh | EurekAlert!
Further information:
http://www.earth.columbia.edu/news/2005/story03-07-05.html
http://www.columbia.edu

More articles from Earth Sciences:

nachricht Early organic carbon got deep burial in mantle
25.04.2017 | Rice University

nachricht New atlas provides highest-resolution imagery of the Polar Regions seafloor
25.04.2017 | British Antarctic Survey

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

NASA's Fermi catches gamma-ray flashes from tropical storms

25.04.2017 | Physics and Astronomy

Researchers invent process to make sustainable rubber, plastics

25.04.2017 | Materials Sciences

Transfecting cells gently – the LZH presents a GNOME prototype at the Labvolution 2017

25.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>