Score another point for Portland, the king of green cities.

Ahh, sprawl. It makes us totally dependent on our cars, increasing traffic and pollution. It obliterates open space, destroying wildlife habitat and healthy ecosystems. It strains once-thriving downtown areas, leading to all sorts of urban decay. But according to a new study, it's not as bad as we think it is.

The study, called "Causes of Sprawl: A Portrait from Space," compared data from 1976 (high-altitude photos) and 1992 (satellite imagery) and found that the overall, the amount of open space surrounding individual houses has not changed. According to a press release about the study, "Forty two per cent of land in the square kilometre surrounding the average residential development in 1976 was open space, compared with 43 per cent in 1992."