What Can We Learn From Orientation

This week's popular distraction on the geo-webs is an app that draws every street in a city (or other location) colored by orientation. Here is one of my favorite personal places, Philadelphia.

While seemingly just a meaningless distraction the colors do tell you something about settlement patterns. Settled on a part of the Delaware River that runs due south and then west, the major part of the city is along an almost north-south (red) grid. However most of the river flows at about a 45 degree angle and much of southeastern Pennsylvania is on a grid shaped by the river's direction (the purple and blue lines). In the outer parts of the city these grids collide creating some of the more interesting urban spaces in the city (IMHO). Here is the southeastern part of Pennsylvania. I expected to see more purple but there is still quite a bit in the northern regions of the metro area where I grew up.

Note that the app allows you to change the background color. For most of these images I set it to black because the roads show up more clearly. 

For a more meta view here is all of Pennsylvania.

I do not recommend loading an entire state as it takes a while and may overwhelm your computer (and their server).

Points of interest include the colorful twists and turns of the central valleys and ridges, the separately unique Lake Erie grid, and the holes in the northern forests where no roads run. As a different type of city Pittsburgh, one of the toughest cities in the country to navigate, is quite colorful. There are still many grid neighborhoods but they run at all kinds of angles, often at the whims of the rivers.

Pittsburgh-taste the rainbow!

For a suburban view, here is the area around my childhood home in Levittown, PA. The blue lines in the upper left corner are from a shopping mall parking lot.

Many cities in the western half of the United States strictly follow the township and range grid of the public land survey system. Often the downtown areas run at an angle either to follow a railroad or to accommodate an older grid system. Here is Denver. 

Denver-embrace the yellow!

As a proof of concept here are four other cities with a similar pattern.

I could go on about this for way too long but I'll end with an artistic mashup of some of the more interesting and colorful places I've explored in Philadelphia. You can explore you favorite places here.
 

Clockwise from top left - the art museum area, the effect of the Schuylkill River bends, roads curving around the airport runways, the way Roosevelt Boulevard breaks up the northeast grid, some curvy suburban colors, and a difficult to see Logan Circle.