Human geography, like other social science disciplines, has it fair share of models. Models are abstractions or simplifications of the inner working of complex phenomena that exist in the real world. We build models to reflect out understanding of how things work. The models will provide us with a way to describe phenomena as well as to explain and even predict them.
In geography, the globe is one of the best known models. It is a model of the earth and we can use it to visualize how the earth works in relation to lots of things including night and day, seasons, climate, air flow, etc.
Maps are also brilliant models of the earth. Depending on our needs, we can simplistically represent the entire earth on a map, or just a single street block to show homes that were built in a particular style.
It is often said that that in the 1800s, the French were the first to start representing intangible things on thematic maps. However, this is not true. Way back in antiquity, the Greeks figured out the shape of the earth and started representing climate zones on maps. Today, most maps are used to represent intangible things like temperature, disease rates, homicide patterns, income distribution, etc. Maps depicting these things are also models.
In Geography, when we speak about classical models, we are talking about a set of models beginning with Weber in 1909 that sought to explain industrial location, agriculture land use, location of cities in a region, internal land use of cities, lmigration patterns, transportation patterns, economic growth, territorial behavior of states, etc.
Two decades ago, these models were the foundation of geography programs in the US and elsewhere. Today, many geography majors have never even heard about these models. Yet, these foundation models continue to provide us with a way of thinking about spatial patterns and their logic and conclusions are prevalent in current geography textbooks. Also, some disciplines such as urban and regional planning still rely heavily on some of the theoretical work of this era to guide settlement planning.
In modern geography, the concentration known as spatial analysis is firmly connected to the geospatial sciences and continues to directly extend the work of classical model builders in geography. Spatial analysis takes, as it starting point, the need to understand spatial patterns. Space rather than place is the central focus and the goal is to build mathematical and computer models to represent, explain and simulate patterns created by natural and human processes on the landscape.
Models in spatial analysis have practical applications and relevance across a broad range of disciplines. However, because they are often taught without reference to their historical connection to geography, people often fail to see the connection between current spatial modeling and classical models in geography.
In my own dealings with spatial analysis, I try not to lose sight of the classical problems in geography because they represent the historical basis of spatial analysis as well as the type of problems that geographers are interested in solving. It is true that the way we approach problems in geography changes with time and technological developments, but the core nature of the problems remain constant.
Below is a list of some classical models in geography. Scrutinizing the list, you will notice that the common interest is solving problems related to spatial patterns.
Location of Economic Activities
- Agricultural location theory – Johann von Thunen (1826)
- Least Cost Industrial location theory – Alfred Weber (1909)
- Locational Interdependence – Harold Hotelling (1929)
- Profit Maximization – Losh (1952)
System of Urban Places
- Central Place theory – Walter Christaller (1933)
- Rank Size Rule
- Primate Cities
Internal Structure of Cities
- Concentric Zone theory of urban land use – Burgess
- Sector theory of urban land use – Hoyte
- Multiple Nuclei theory of landuse – Ullman/Harris
- Bid-Rent Theory – William Alonso (1964)
- Vance urban realm theory
- Growth Pole theory – Francois Perroux (1949)
- Polarization effects -Albert Hirschman, i.e., the negative impact of a growth pole on surrounding regions. Trickling down refers to the positive impact of a growth pole or growth center on adjacent regions.
- Backwash and spread effects – Gunnar Myrdal, Swedish economist. These are the same concepts as polarization and trickling down.
- Rostow’s stages theory of economic development
- Core periphery model – John R. Friedman
- World Systems theory – Immanuel Wallerstein
- Demographic transition model
- Malthus Population Growth Model
- Gravity model
- Ravenstein laws of migration
Spatial Diffusion – Torsten Hägerstrand