124 Thirty-eight urban regions
(8) Saltwater intrusion into aquifer (Barcelona).
(9) Aquaculture area (Bangkok).
(10) Demilitarized zone (Seoul).
(11) Oasis and fort in use (Rahimyar Khan).
(12) Native People’s land (Edmonton, San Diego/Tijuana).
(13) Transportation tunnel entrance/exit (London).
(14) Concentrated greenhouses (Barcelona).
(15) Large recently logged clearcuts (Canberra).
(16) Intermixture of cropland, small-tree farming, and bits of natural vege-
tation (Cairo, Rahimyar Khan).Nuclear power plants, though not mapped, operate in 17 of the 31 nations
represented in this analysis (John P. Holdren, personal communication), and are
present in several of the 38 urban regions. Recently the nuclear power plants in
theLondon and Portland urban regions have been decommissioned with fuel-
cells removed. In the Portland case the facility was then dynamited into oblivion.
Numerous published maps were used to aid in mapping areas and sites within
urban regions, the most common being: national and regional road maps; world
atlas maps; DeLorme topographic maps (USA); National Imagery and Mapping
Agency (declassified) maps (USA); keyhole website maps. When in doubt, the
pattern visible on the 30 m-pixel Landsat aerial image was used.
Built areas mapped are mainly intermixed residential and commercial areas.
Since residential and commercial areas have very different effects, both as areas
and as sources and sinks, future work might usefully separate them. Similarly,
future work might differentiate areas by population density, socioeconomic sta-
tus, and so forth, since the effects on the areas and on surrounding areas, are
so different. Future work might also usefully include power sources, such as
hydro, nuclear, coal, biomass, wind and solar, since the effects of production
and transport on the urban region markedly differ. Also mapping other hazard
areas, such as earthquake (Sapporo, Mexico City, San Diego), cyclone/hurricane
(Bangkok, Kagoshima), and volcanic eruption probabilities, is desirable. Inter-
city rail lines were omitted since their trains only stop in the city, but mapping
rail stations for commuters outside the metropolitan area would be valuable.
Adding such common urban history and planning parameters to the major pat-
ternsexplored in these analyses should provide valuable added insight into the
big picture.
Finally, people knowledgeable in specific urban regions and who have expe-
rience with mapping will know that all boundaries, land-cover types, and sites
marked should be considered approximate, and that all the maps are incomplete
and probably contain, hopefully minor, errors. More complete maps with these