Google has already populated the urban cores of many cities in Google Earth with 3-D buildings—but as Google product manager Mark Limber explained to me in an interview, the company needs help from Netizens to build out the surrounding areas. So it built a Web-based tool that lets anyone draw basic 3-D shapes on top of the aerial images, then line them up in 3-D space from several points of view. Google uses the 3-D information to represent the buildings inside its virtual globe and to “texture” their exteriors with the proper sections of the photos. I explain the whole thing in my Friday, November 20 World Wide Wade column on Xconomy.

I started out by building a model of my own apartment building, James Court, in Boston’s South End. It was fairly straighforward, since the building is a simple L-shape with flat roofs and not too many protrusions. Here’s an image of the finished model; to see it in Google Earth, go to the model’s page in Google’s 3-D Warehouse and click on “View in Google Earth.”

This morning I tried my hand at a slightly more complex building, Franklin Square House at 11 E. Newton St. It’s a fairly famous building, and one with which I’ve long had a minor fascination, because it was used in exterior shots to represent the fictional St. Eligius Hospital in the 1980s NBC TV drama St. Elsewhere—one of my favorites at the time. A little research reveals that the building started out in 1867-1868 as the St. James Hotel (which must be where the James Court architects got the name) and was known throughout the 1870s as the South End’s finest hotel. President Ulysses S. Grant stayed there in 1869. Later it was the headquarters for the New England Conservatory of Music, then—from 1901 to 1970—a non-profit hotel for young working women, including nurses who worked at nearby Boston City Hospital (now Boston University Medical Center).

These days Franklin Square House is an apartment building for senior citizens. Every once in a while I see tourists staring at the building from Franklin Square Park across the street—they probably remember it from the famous opening sequence of St. Elsewhere, where Orange Line trains rumbled past on the the Washington Street elevated railway (which was demolished, thank goodness, in 1987). In fact, I made an Orange Line pilgrimage to the neighborhood once back in 1986 or so, when I was a freshman at Harvard and I wanted to see “St. Eligius” for myself. The neighborhood was in awful shape at the time—decaying and poverty-stricken—and it’s amazing what a transformation has occurred here over the last 20 years.

Here’s the model, below; to see it in Google Earth, go here and click on “View in Google Earth.” By the way, if you notice a few architectural echoes of Franklin Square House in James Court, you’re not imagining things. The ribbed aluminum cladding around the top floor of James Court, for example, is a direct reference to the neighboring building’s graceful mansard roof. You have to look at the buildings side-by-side, in person, to recognize all of the consistencies in the two designs; to my mind, the James Court architects, Childs Bertman Tseckares, did a great job of honoring a grand old Victorian building in their 2005 modernist creation.

The point being that I only got through three projects in that first column—on art, writing, and photography—before I ran out of time and space. Last week, I finished two more, on audio self-publishing and computer animation. In today’s third and last installment, I want to suggest two final projects that will give you a chance to express yourself in digital media that may be a little less familiar: maps and 3-D virtual worlds.

6. Put Yourself on the Map with Platial

Mapmaking hasn’t traditionally been seen as a craft open to amateurs, or even one where self-expression is encouraged. A map, after all, is a public resource, and is supposed to be objective and accurate, right? Well, maybe in theory. In practice, the digital revolution is transforming the meaning of maps just as drastically as it’s changing the way we think about music and news and other forms of communication.

This is an excerpt from my September 18, 2009 World Wide Wade column. Click here to continue reading the column at Xconomy.