Urban geography examines cities and how they change over time. It analyzes the internal structure of cities and relationships between cities. There are four traditions in urban geography: physical, human-environmental, regional, and spatial. In recent decades, trends include the rise of global cities, feminist perspectives, studying urban culture, and using GIS technology. The Chicago School emphasized systems of cities while the Los Angeles School stressed how hinterlands influence cities. New Urbanism promotes sustainable, pedestrian-oriented development.