IB Geography HL — The variety of urban environments

Key Idea: Topic 13.1 is about why a city is not laid out at random — why shops, offices, factories and housing each end up where they do. Its single micro pulls three strands together: Land values & bid-rent — the price of land peaks at the Central Business District (CBD) and falls outwards, so the activity that can pay most wins the most accessible, most expensive site. Land-use models — the concentric (Burgess) rings and the sector (Hoyt) wedges are two simple maps of how those zones sort themselves out. Why activities locate where they do — physical (flat, coastal land), economic (land value, accessibility) and political (planning, zoning, regeneration) factors decide the detail. This is Option G (Urban environments) content, examined on Paper 1. SL students answer two options and HL three (the same questions), each ending in a 10-mark Examine/Evaluate essay marked on markbands.

🏙️ Land values & bid-rent — the spine of the topic

The single most important idea in this topic is land value: the price (or rent) of land is highest at the CBD and falls with distance towards the urban edge. This is the bid-rent idea — each land use will only pay so much for a site, and the highest bidder wins. High-footfall retail and offices out-bid everyone for the costly core; housing and industry are pushed out to cheaper land. The skill examiners test is to read a bid-rent graph or urban map, describe the falling trend (quote a figure with units), then explain why land values vary and why each activity sits where it does.

Tip: For a bid-rent graph or urban map, describe the trend first — land value is highest at the CBD (index 100) and falls to about 8 at the edge, with the steepest fall in the first 3 km. Quote a figure with units. Then explain it with accessibility and bid-rent.

📐 The land-use models — Burgess rings & Hoyt sectors

Two classic models summarise how the zones sort out. Burgess (concentric) sees land use in rings around the CBD; Hoyt (sector) improves on it by adding wedges that follow transport routes. Both are simplifications — examiners want you to use them as a framework, then add the role of physical site and planning.

🌍 Why activities locate where they do — real cities

Land value sets the broad pattern, but physical, economic and political factors decide the detail. Examiners want the mechanism — name a factor, then explain how it pushes an activity to a site. Always develop the chain, never just list.

Example: In Barcelona, the flat coastal plain held the dense grid-iron CBD, while industry took the level land by the port — a physical control. Planning then converted the old industrial seafront for the 1992 Olympics into housing and leisure — a political control reshaping land use. In Singapore, tight government zoning deliberately places industry on reclaimed coastal land and high-value finance in the CBD — land use here is planned, not left to the market.

Example: In Lagos (a fast-growing megacity), formal jobs are too few for the population, so a vast informal economy — street trading, small workshops, repair stalls — fills the gap, clustering on cheap, accessible roadside land. In Detroit, the collapse of car manufacturing left huge areas of derelict factories and housing — when the economic activity that paid for the land vanished, the land use emptied out.

Don't just name a factor — show the chain. Flat coastal land → cheap + accessible → industry locates there. High CBD land value → only retail/offices can pay → housing pushed out.

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