All Streets

all streetsNew work, now posted. All of the streets in the lower 48 United States: an image of 26 million individual road segments. This began as an example I created for one of my students in the fall of 2006, and I just recently got a chance to document it properly.

Nothing particularly genius about this piece—it’s mostly just a matter of collecting the data and creating the image. But it’s one of those cases where even in a (relatively) raw format, the data itself is quite striking.

The data in this piece comes from the U.S. Census Bureau’s TIGER/Line data files. The data is first parsed and filtered (to remove non-street features) using Perl. Next, using Processing, the latitude and longitude coordinates are transformed using an Albers equal-area conic projection (which gives it that curvy surface-of-the-Earth look that we’re used to), and then plotted to an enormous image that’s saved to the disk. The steps are similar to the preprocessing stages described in Chapter 6 of Visualizing Data.

I had originally hoped to use this piece to show patterns in street naming, but I didn’t manage to find as much as I had hoped. For instance, names of local trees and flowers being tied to the local geographic regions where they’re found. However, cookie cutter suburban neighborhood developments seem to have obliterated any causation. “Magnolia” is such a nice sounding, outdoorsy word; who wouldn’t want it adorning their street corner? Local flora be damned.

There are, however, a few other interesting tidbits in the data that I hope to cover in a future project. Real work be damned.

Friday, April 25, 2008 | allstreets  

Visualizing Data Book CoverVisualizing Data is my 2007 book about computational information design. It covers the path from raw data to how we understand it, detailing how to begin with a set of numbers and produce images or software that lets you view and interact with information. When first published, it was the only book(s) for people who wanted to learn how to actually build a data visualization in code.

The text was published by O’Reilly in December 2007 and can be found at Amazon and elsewhere. Amazon also has an edition for the Kindle, for people who aren’t into the dead tree thing. (Proceeds from Amazon links found on this page are used to pay my web hosting bill.)

Examples for the book can be found here.

The book covers ideas found in my Ph.D. dissertation, which is the basis for Chapter 1. The next chapter is an extremely brief introduction to Processing, which is used for the examples. Next is (chapter 3) is a simple mapping project to place data points on a map of the United States. Of course, the idea is not that lots of people want to visualize data for each of 50 states. Instead, it’s a jumping off point for learning how to lay out data spatially.

The chapters that follow cover six more projects, such as salary vs. performance (Chapter 5), zipdecode (Chapter 6), followed by more advanced topics dealing with trees, treemaps, hierarchies, and recursion (Chapter 7), plus graphs and networks (Chapter 8).

This site is used for follow-up code and writing about related topics.