Saturday, September 04, 2010

Thinking about getting from place to place

Measuring distance in miles has a long history; the word "mile" comes from the Latin for 1000, and a mile corresponds to 1000 paces of a Roman legion. When we map all the distances among points on the earths they fit perfectly on a globe, and reasonably well on a flat map of a small part of the surface of the earth. The system is beautiful, and easy for us to comprehend especially with the visual aids of maps and globes.

There are other ways to measure distance between points. For example, one can measure the distance one actually has to travel to get from point A to point B. In cities, we use a city block measure. Think of a simple example of 100 yard square blocks, in which you have directions to walk three blocks east and then four blocks north to get from A to B. The map distance between the two points is 500 yards (by the Pythagorian theorum), but you actually have to walk 700 yards to make the trip. A bird may fly directly, but on city streets we walk only on the edges of the blocks, not across them. Note too, that in real cities as one drives from A to B, the distance might not be the same as that driving from B to A (if for example there are one-way streets).

One can also measure the time it takes to go from A to B. The measure can be very different than the measure of the miles from A to B. Were I to take a trip from my home near Washington to New York it would take about as long to go from my house to the airport as to go from the Washington airport to the New York airport although the distances are in a ratio of roughly one to ten.

Another measure would be the cost of travel.

Note again that in these measures, the value from A to B may not be the same as the value from B to A. If you have ever climbed a mountain you know that the time it takes to climb from the base to the top is much longer than the time it takes to descend from the top to the bottom. In the 19th century it would take longer and cost more to travel by boat from New Orleans to St. Louis than to travel from St. Lewis to New Orleans.

For all of these measures of the difficulty of traveling from place to place there is no simple two or three dimensional image one can make of the complete set of distances, which makes the sets hard to visualize. We tend to use reduced tables of "distances" among sets of key locations.

The difficulty of getting from place to place differs according to what is moving. Compare moving people, freight and information. It takes a few hours for someone to travel from East Africa to Europe by plane, a similar time for cut flowers to make the trip from East Africa to European flower markets, days for bulk shipments to make the trip, and miliseconds for information to make the trip by telecommunications.

Obviously the difficulties of getting from place to place have changed with changing technology and changing infrastructure. When Homo sapiens lived in small hunting and gathering groups, people walked. If they moved things from place to place they did so carrying them at the same walking pace. Information too moved at a walk. The changes to this system are obvious as is their relation to the changes in technology. The Incas had a system of runners with quipus who carried information more quickly over long distances than any person could travel in their society. The ancient Persians had a system similar to the pony express in the American west that moved information rapidly for the time. These systems were expensive, so expensive that they tended only to serve the government, and had very limited bandwidth -- they could not move very much information per unit time. Similarly systems like the native American smoke signals or the French 18th century telegraphs (signal towers located in long lines that allowed signals to be transmitted from tower to tower) similarly moved information faster than a man or a horse could travel, at relatively high cost, with very limited information transmission capacity.

The relative difficulties of different modes of transportation have changed with changing technology. As suggested above, man evolved when people, goods and information all moved at the same speed and cost. Today people move sometimes by foot or animal power, but can also move in cars or trains, or even airplanes. Freight tends to move more slowly than people, but at lower cost per unit distance. Information however can move literally at more than lightning speeds.

I suspect that the different rates of change of the ease of movement of different things has profound implications for society. Clearly the increasing pace of movement had major implications for the industrial revolution and the second technological revolution (based on such things as the internal combustion engine and electification).

Think also of the changing distribution of energy over the man-built world. At one time people had only the energy that they could generate with their own muscles and wood fires. By the time of Columbus, some societies had added animal energy, wind mills, and water mills as sources of energy, while the American societies still had on the llama for animal energy. Today we have added fossil fuel and electricity generated from fossil fuel, nuclear plants and hydopower. The energy available where people live is available to drive motion of people, freight and information. The global distribution of energy availability is very uneven. There are places in Africa and Asia where there is no electricity, little coal or oil, and few animals. Those of us in urban areas in the United States have comparatively much larger amounts of energy available/

Think also of the changing distribution of people over the man-built world.  Human population has grown exponentially over a couple of centuries. For the first time, more than half of the human population is to be found in cities. While it is increasingly possible to conduct transactions between people over great distances, it seems likely that more and more transactions are conducted among people located close together in the same city. This fact too modifies the speed with which people, goods, services and information can be delivered.

No wonder things seem to be moving faster and faster, and people are having more and more difficulty adjusting to the increasing pace of life.

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