Sea Travel And The Grid Street Pattern

This posting will later be moved to the world and economics blog, www.markmeekeconomics.blogspot.com .

If you wonder what sea travel has to do with the grid pattern of streets that is seen in many cities and towns, read on.

Have you ever wondered how sea travel affects the way things are done on land? I had an interesting thought recently that I have never seen anywhere else.

Sea travel almost always consists of the boat moving in a straight line from one port to another. It is usually a matter of setting the boat in one compass direction, and then continuing from there. Right angles generally do not occur in nature, the major exception being that the surface of the earth forms a two-dimensional surface, at least from our local perspective, with four cardinal compass directions. Direction at sea can be determined with a magnetic compass, although use of the stars is more accurate because the magnetic north and south poles are not exactly the same as the geographic poles.

Travel on land is historically much less in straight lines than at sea. The local terrain is far more of a factor in travel on land than at sea.

Square or rectangular is usually the most efficient shape for a building, although this is not as important when it comes to street patterns. As we saw in "Social Engineering", on the world and economics blog, use of the grid pattern in the streets improves the spatial efficiency of buildings, relative to non-grid street patterns, but makes it so that one has to travel a further distance to get from one point to another unless the destination is on the same street as the starting point.

Pre-planning is necessary to set up a town or city with a grid street pattern. But towns historically have just grown, rather than having been planned, and then have merged together. Local terrain and pre-existing routes or roads are far more important factors in how a town's street pattern will turn out.

My hypothesis is that humans would never have thought of setting out streets in a grid pattern if not for extensive travel at sea. The grid pattern of streets is generally believed to have begun with the Romans. But the Roman Empire was centered around the Mediterranean Sea, Mare Nostrum means "our sea" in Latin. Ships full of grain from Egypt would set a straight-line course for the opposite side of the Mediterranean.

The city of Gloucester, in England, for one example originated in Roman times (as does any town in England with a name ending in -caster, -cester or, -chester). The city was originally built around four streets in the compass directions, Northgate, Southgate, Eastgate and, Westgate Streets. It can be seen in the satellite imagery that those streets still remain, and there is a grid pattern to the streets along the docks on the Severn River. But, other than that, the grid pattern was abandoned as the city grew during the Middle Ages.

Even after Europe began the Age of Discovery by ship, the grid pattern of streets remains rare in Europe. But North American towns and cities are overwhelmingly built around the grid pattern. How is it that the Europeans who settled North America came from a continent where the grid pattern of streets is very much the exception, rather than the rule, but yet they built almost exclusively in this apparently foreign pattern after crossing the ocean by ship?

The only logical answer is that it was the long journey in a straight line by ship, guided by the compass or stars, that planted the idea of setting out the streets in their destination in straight lines by the compass directions.