QuickBird imagery of Beijing urban area, acquired on Sep. 30 of 2003 (off-nadir viewing angle: 9.3 degrees) was used in the study.
The QuickBird imagery contains four multispectral bands with the spatial resolution of 2.44 m (blue, green, red, and near infrared band) and a panchromatic band with the spatial resolution of 0.61 m.