Sometimes you need to step back to see something clearly. Sometimes this means stepping way, way back. Otherwise, to update an old saying, you can't see the city for the houses.
In fact, in the relatively new science of studying urban areas that phenomenon is exactly the problem when studied at the ground level, a city is such a complicated conglomeration of features that it is hard to make useful generalizations that allow researchers to define different kinds of cities models that explain key differences that exist between one city and another.
What a difference 700 km. makes. Using data analysis techniques developed for research activities in the Central Arizona Phoenix Long Term Ecological Research Project, Arizona State University geologists William Stefanov and Philip Christensen have turned to satellite data being gathered on 100 cities around the globe by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra spacecraft, a satellite in polar orbit. In a preliminary analysis of 12 cities, the researchers have found three significant configurations of urban development that they believe can be used to classify cities by their growth and density patterns.
The research represents the first results of the ASTER Urban Environmental Modeling Project and will be presented at a press briefing at the American Geophysical Union spring meeting in Boston on at 1 p.m. on May 29.
"We're going to collect data over each of 100 cities twice a year, both day and night," explains Stefanov, a researcher at in ASU's Department of Geological Sciences and the Center for Environmental Studies. "The whole idea is to be able to classify the land cover of those cities, differentiating vegetative vs. non-vegetative, urban vs. non-urban, developed vs. undeveloped areas and to track them over six years to begin to see how these cities are changing over time and how they're interacting with their surrounding environment."