Urban Hierarchies, Central Place Theory & South-African Case Studies

Urban Hierarchy: Concept & Structure

  • A hierarchy ranks settlements according to size, population, services and overall importance.
  • Classic South-African order (largest ➜ smallest):
    • Conurbation
    • City
    • Large town
    • Small town
    • Village
    • Hamlet
    • Isolated dwelling / isolated place
  • As one moves up the hierarchy:
    • Population, physical area and number of services all increase.
    • Settlements become less frequent.
  • As one moves down the hierarchy:
    • Settlements become more numerous but have smaller population and fewer services.

South-African Examples by Hierarchical Level

  • Isolated dwelling / hamlet: scattered farms, individual rural homesteads in Eastern & Western Cape.
  • Village: Drummond, Wilderness.
  • Small town: Examples mentioned on p. 11 image (“Country Town” photo) incl. many rural service centres.
  • Large town / Major town: Boksburg, Brakpan, Alberton, Bedfordview, Alexandra, etc.
  • City / Provincial capital: Johannesburg (Gauteng), Pietermaritzburg (Kwa-Zulu Natal), Bisho (Eastern Cape).
  • Conurbation: The Witwatersrand (Johannesburg-Boksburg-Brakpan-Benoni-Roodepoort-Randburg-Sandton-Edenvale-Soweto-Alberton-Midrand) that now merges with Pretoria/Tshwane.
  • Primate metropolitan area: Johannesburg–Pretoria acts as the national economic core and dominates other cities.

Spatial Distribution of Larger Urban Places in SA

  • Concentration in Gauteng (appears almost continuously urbanised).
  • Second band along the eastern seaboard (Durban, East London, Port Elizabeth/Gqeberha).
  • Cape Town dominant in the far west.
  • Interior plateau and West Coast have comparatively few urban centres.
  • Origins of Gauteng cities largely linked to discovery of gold along the Witwatersrand.

Gauteng as the “Economic Heart”

  • Contains the national capital Pretoria/Tshwane and provincial capital Johannesburg.
  • Heavily industrialised with excellent transport & electricity (Vaal River water, Mpumalanga coal-fired power).
  • Offers best employment opportunities in SA; therefore attracts migrants.
  • Urban expansion has fused many towns into a continuous conurbation.

Capital Cities vs. Urban Size

  • Provincial capitals are not always the largest city in their province:
    • Kwa-Zulu Natal: capital = Pietermaritzburg, but Durban is larger.
    • Eastern Cape: capital = Bisho (historically chosen during Homeland era) while Gqeberha (Port Elizabeth) and East London are bigger.

Key Definitions

  • Hierarchy: system of ranking items/places according to importance or size.
  • Dormitory town: settlement where residents mainly sleep but commute to a nearby large city for work.
  • Satellite town: small, semi-independent town economically dependent on a nearby larger one (similar to dormitory town).
  • Zoom town: small town experiencing in-migration by remote workers (“semigration” within national borders).
  • Semigration ≠ emigration; one is internal relocation, the other crosses national boundaries.
  • Conurbation: continuous urban area formed when several settlements grow outward and merge.
  • Megalopolis: chain of adjacent conurbations that have coalesced (e.g. North-Eastern Seaboard of USA – 1000\text{ km} continuous urban sprawl).
  • Urban sprawl: formless, low-density expansion of urban footprint into surrounding countryside.

Population Contrasts Inside the Hierarchy

  • Example given:
    • Sandton population ≈ 13500 (GeoNames) yet offers extensive high-order services ➜ ranked high.
    • Alexandra population ≈ 1.3 million, hosts 80\% of Johannesburg’s taxis yet ranks lower due to fewer services & functions.
  • Implication: Number of people alone does not dictate a place’s hierarchical level; diversity & sophistication of services matter more.

Central Place Theory (CPT)

  • Proposed by German geographer Walter Christaller (1933).
  • Explains size, spacing, number & functions of urban settlements through economic logic.

Core Assumptions

  • Consumers seek convenience & lowest possible price.
  • Firms aim to maximise profit.
  • Greater distance = higher travel cost ➜ people minimise travel costs.
  • Terrain is an “idealised isotropic plain” in original model (equal accessibility everywhere).

Key CPT Concepts

  • Low-Order Goods / Services:
    • Everyday, cheap, nonspecialised (e.g. daily newspaper, bread, haircuts).
    • Low threshold population, short range, found in many small centres.
  • High-Order Goods / Services:
    • Expensive, specialised (e.g. furniture, large electrical appliances, financial/legal expertise).
    • High threshold, long range, offered only in larger centres.
  • Range (R): maximum distance consumer willingly travels for a good/service.
  • Threshold Population (T): minimum number of customers needed to keep a business viable.
  • Market Area / Sphere of Influence: region from which a central place draws customers.
  • Spatial Competition: neighbouring centres compete for the same consumers; price/service incentives alter boundaries (e.g. “R15 for 5\,\text{kg} packet” vs. “pay R20 and get +2\,\text{kg} free”).

Hierarchical Pattern Predicted by CPT

  • Many small centres, few large centres.
  • Larger centres spaced further apart yet possess bigger spheres of influence.
  • Hexagonal market areas minimise overlap & gaps (Christaller’s diagram).

Lower-Order vs. Higher-Order Centres (Table-style bullets)

  • Lower-order centre:
    • Numerous; close together.
    • Small population.
    • Mainly low-order goods/services.
    • Small T and small R.
  • Higher-order centre:
    • Few; spaced farther apart.
    • Large population.
    • Offers full spectrum from low- to high-order services.
    • Large T and large R.

CPT Rules Summarised

  1. Settlements with larger populations support more functions.
  2. Low-order goods more numerous than high-order goods.
  3. More small settlements than large settlements (inverse frequency-size relationship).

Retail Geography: Fast-Food Outlet Example

  1. Threshold population: minimum customers needed so outlet avoids bankruptcy.
  2. Sphere of influence: catchment area of the outlet.
  3. Range: furthest distance customers are willing to travel for the food.
  4. Competitive outcomes if two outlets open nearby:
    • One fails,
    • Both survive via agglomeration effect,
    • One buys out the other,
    • Cluster attracts further outlets (possible emergence of a specialised “food node”).
  5. Factors determining viability/location:
    • Local population size & income,
    • Age profile,
    • Existing competition,
    • Type of cuisine,
    • Position within shopping centre (anchor tenant proximity).
  6. Anchor tenant: large store in mall that increases overall footfall.
  7. Chain store: branded outlets with central management & standardised practices.

New SA Place-Name Updates (since 2021)

  • Port Elizabeth ➜ Gqeberha.
  • Port Elizabeth International Airport ➜ Chief David Stuurman International Airport.

Image / Diagram References (verbal descriptions)

  • Page 2: Stock images of Indian forest landscape and huts – contextual visuals for isolated dwellings/villages.
  • Page 7 & 8: Map/photo of North-Eastern US megalopolis showing 1000\text{ km} urban corridor from Boston to Washington DC.
  • Page 9: Aerial view photo depicting low-density urban sprawl and declining population density outward from core.
  • Pages 10–13: Sequence of icons representing hierarchical levels (local service centre, country town, major country town, minor country town, metropolitan area, major metropolitan area, primate metropolitan area).
  • Page 17–18: Comparative population figures for Sandton vs. Alexandra highlighting service disparity.

Ethical / Practical Implications

  • Urban sprawl consumes farmland & green space ➜ environmental sustainability challenges.
  • Service inequality: high-order services concentrate in affluent, low-population nodes (e.g. Sandton), while dense townships (e.g. Alexandra) remain underserved; raises social-justice and planning questions.
  • Semigration & zoom towns: digital connectivity enables economic redistribution but can inflate rural housing markets and strain small-town infrastructure.
  • Selection of provincial capitals often influenced by political history, not just functional efficiency (e.g. Bisho’s homeland legacy).

Key Take-Home Equations & Values (LaTeX Format)

  • Range: R = \text{max distance willing to travel}.
  • Threshold: T = \text{min customers to break even}.
  • Continuous urban corridor length (NE USA): \approx 1000\,\text{km}.
  • Sandton pop.: 13500; Alexandra pop.: 1.3 \times 10^{6}.
  • Promotional example: buy 5\,\text{kg} at R15 vs. R20 for 5\,\text{kg}+2\,\text{kg}.

Study Tips

  • Be able to reproduce the hierarchy list and match South-African examples.
  • Know how to classify goods/services into low vs. high order.
  • Practise drawing Christaller’s ideal hexagonal pattern and label range, threshold & sphere of influence.
  • Analyse any town’s rank by asking: population? service diversity? regional influence?
  • Remember political exceptions (capital ≠ largest city).