The Gravity Model is used to predict the degree of interaction between two cities based on their size and the distance between them.
The mathematical logic suggests that larger cities exert a stronger 'pull' on people, ideas, and commodities than smaller cities.
The basic formula for interaction () between city and city is: where represents population (or economic mass) and represents the distance between them.
In the context of globalization, world cities like London and New York maintain extremely high levels of interaction despite the physical distance () because their economic 'mass' () is so significant.
It is vital to distinguish between a city's physical size and its global influence.
| Feature | Megacity | World City |
|---|---|---|
| Primary Criterion | Population (10 million+) | Global economic/cultural influence |
| Location | Mostly in LDCs (Periphery) | Mostly in MDCs (Core) |
| Function | Regional service/housing hub | Node in the global network |
| Challenge | Infrastructure strain/poverty | Maintaining global competitiveness |
A city can be both a megacity and a world city (e.g., Tokyo), but many megacities lack the global financial reach to be considered world cities.
Identify the 'Why': When asked about world cities, focus on their function (finance, MNCs, culture) rather than just their size.
Gravity Model Application: Remember that the 'distance decay' effect is often mitigated in world cities by advanced telecommunications; two global hubs may interact more than two neighboring small towns.
Check the Hierarchy: Always look for terms like 'nodes,' 'networks,' and 'hubs' when describing globalization in an urban context.
Common Distractor: Do not assume every capital city is a world city. A capital may have political power but lack the global financial markets required for world city status.
Size vs. Influence: Students often mistake high-population cities (Megacities) for World Cities. Influence is measured by the flow of capital and information, not just the number of residents.
Distance Decay: A common misconception is that distance always prevents interaction. In the modern era, 'time-space compression' allows world cities to remain tightly linked regardless of physical miles.
Homogeneity: While world cities share many traits, they are also 'melting pots' with unique cultural identities formed by international migration.
