IB Geography Option G: Urban environments

What Option G covers

Option G starts with the variety of urban environments: site and situation, primate cities, and the models of land use within a city, from bid-rent theory to Burgess's concentric zones and Hoyt's sectors, with informal settlements and the informal sector. Changing urban systems: suburbanisation, counter-urbanisation and reurbanisation, gentrification, deindustrialisation, urban sprawl and the reuse of brownfield sites. Urban environmental and social stresses: the urban heat island, photochemical smog and temperature inversions, congestion, segregation and gated communities. Building sustainable urban systems for the future: congestion charges, park and ride and bus rapid transit, green belts and compact cities, and eco-cities, smart cities and resilient cities.

Where students slip

• A settlement's site is the land it is built on, such as a river terrace or a defensible hill. Its situation is where it sits in relation to the places and features around it, such as a crossing point or a coast.
• Suburbanisation is moving out to the edge of the city, which still grows the urban area. Counter-urbanisation is leaving the city altogether, for smaller towns and the countryside beyond.
• A primate city is defined by its size relative to the next largest city in its country, more than twice as big, not by being the capital or a megacity.