The text is based upon material found in Places and Region in Global Context: Human Geography 4th ed. by Paul Knos and Sallie Marston, Prentice Hall, Upper Saddle River New Jersey.
In order to better understand the world, geographers employ the following tools of spatial analysis. The first of these is location. Locations can be spatially specific (that is defined mathematically on a map by latitude and longitude) or they may be relative. The invention of the Global Positioning System (GPS) has simplified the process through which the latitude and longitude of any given point can be located. The GPS consists of twenty-one satellites and three spares that orbit the earth broadcasting time and location information. The GPS is owned and operated by the government of the United States.
Relative location refers the site and situation of a place. The site of a place can be depicted by the description of its physical characteristics. The physical characteristics of a site may include its elevation, soil, bed-rock, vegetation, and hydrology. The situation of a place refers to its location relative to everything else around it. A place might be considered well situated if it is near transportation routes, medical facilities, shopping amenities, water resources, schools, and the like (some people might not consider these attributes as positive).
The Cognitive aspects of location involve the mental images people have of a place depending on their experiences with it. Places mean different things to different people and one person’s paradise may not be held in high esteem by another. For all of us, there are places of the heart. The farm where I was raised in a rural part of the Willamette Valley of Oregon has special meaning to me, and I continue to remember it as it was when the Valley’s landscape was divided into many small independent farms and dotted with small, picturesque towns nestled securely at the base of the forested Coast Range Mountains to the west. Since the small farms and small towns have given way to agribusiness and urbanization, this landscape no longer actually exits, but it continues to live on in the hearts of those of us who once lived there, once took it for granted, and for whom it will always be home.
Distance is important. Not long ago, three older gentlemen who live in a small town in rural American met, as was their daily custom, at the only café in town for a cup of coffee and an opportunity to present their views of politics, economics, and the problems with the nation’s youth. During this particular coffee hour, one man mused that he believed the greatest invention of all time is the telephone because it has made it possible for people all over the globe to almost instantly talk to each other despite the thousands of miles that may be between them.
Whereas the example of the thermos may indeed represent a great technological breakthrough, unlike the telephone or the airplane, it has had little impact on the power of the friction of distance.
In general, the further one thing is away from another in absolute units of measure, the less influence the two have on one another. Distance however, is also a relative concept. When we travel by automobile, we may measure distance in miles or kilometers. We may also measure distance in time. Therefore, although taking the rural route between two places may in fact shorten the number of miles traveled over taking the freeway, such a route may also significantly increase the amount of time that it takes to reach the destination.
Imagine the significance of distance to every-day life in nineteenth century American in comparison to the impacts of similar differences today. When Andrew Jackson was President of the United States in the 1830s, he occasionally traveled by carriage from Washington D.C. to his home near Nashville, Tennessee. To make these trips required more than a week on the road, and of course, removal from immediate contact with the government. Currently, the President could make this same journey in a matter of several hours, or less, and would be able to maintain continuous contact with his staff throughout the journey. This is an example of time-space convergence.
Distance was at one time a great deterrent to human interaction and also a powerful buffer from threats by other nations or groups. Small towns in rural America once flourished because people could not easily travel to larger urban centers for the consumer goods they required. In the years before the automobile and good roads and highways, a trip of five or ten miles required a great deal of time and effort. Since the creation of freeways and automobiles capable of cruising along at seventy or eighty miles an hour, it is not uncommon for people to commute forty, fifty or sixty miles every day to work. In many parts of rural American, small towns began to wither and die when local farmers could easily bypass the country stores and drive to a county seat or some other larger urban center where the selection was greater and the prices were often lower.
The concept of distance decay basically deals with the observable tendency of human beings to attempt to find what they need with as little effort as possible. Therefore, the greater the friction of distance, the greater the impact of distance decay. Retail businesses give considerable attention to the significance of distance decay when settling on a location for a particular business. They want to understand whether or not a sufficient number of customers will be willing to travel to a given location in order to purchase whatever it is that they are selling. In general, distance-decay is greater for the more ubiquitous goods and services. How far would you travel for a picture hanger, a toothbrush, or a nail? Even if the price and quality of a picture hanger being sold seventy-five miles away was fantastic as opposed to the price and quality of a locally sold adequate hanger, it is unlike that you would be willing to drive seventy-five miles for this superior deal. On the other hand, if you could realize a far better deal on a new car by driving to dealership that was situated seventy-five miles away, you might be willing to make the trip.
Space, in similar fashion to distance, can be measured absolutely, or it may be thought of in relative terms. The size of a space may be fixed by defining its boundaries with lines and points. Areas, planes, and configurations are all spatial concepts.
Ideas, people, goods, diseases, weather systems, political movements, music, literature, etc. all spread from a point of origin somewhere in the world to other places. The way in which such things spread in time and space is called spatial diffusion. In order to analyze spatial interaction, it is necessary to understand the spatial diffusion process. Generally, diffusion occurs in a relatively organized fashion that can be predicted through analyses based on the fundamental principles of distance and movement. Moreover, it is possible to identify spatial tendencies in observable patterns of diffusion.
Expansion diffusion (contagion diffusion) involves the spreading of phenomena through direct contact. For example, if someone finds a way to build a more efficient mouse trap, his neighbors will probably copy it, and they in turn will pass this on to the people they meet. Another example of a recognizable pattern of diffusion is hierarchial diffusion (cascade diffusion). Phenomena spread via this pattern are diffused from one location to another without necessarily coming into contact with people or places situated in between. An example might be the spread of a political idea from one large metropolitan area to another without first passing through people and places in the countryside.