They exist because people choose to live there, invest there, build there, work there, play there. The factors we already considered are important to understanding the urbanization process and also why some cities have been more successful than others. Geography and the natural environment are also important in explaining urbanization and the location of cities. Falling water in the past important for city location. Compare the tree cover of wealthy areas with poor areas.
Vegetation moderates temperatures and increases humidity.
Latitude Linked to climate but also growing season. Elevation High elevation is generally inhospitable to human habitation and therefore cities. Importance of site factors have changed over time. An elegant theory but does not usually translate perfectly in the real world. Treats the natural world as an isotropic, featureless plain.