You may have seen some of the beautiful maps of building ages that have been cropping up around the internet. It first noticed an amazing one of Portland, and then another great one of Brooklyn. 

and BETSY MASON(he is the editor of wired science) says:

I called up Thomas Rhiel of the independent journalism site BKLYNR.com. Rhiel was willing to help, and it turns out he was just the right person to advise me. His map of Brooklyn building ages was his first foray into mapmaking, so he had just muddled his way down the same path I was about to navigate.I’m going to tell you exactly how I made this map. I hope that people with little or no experience making maps will be able to use this as a guide to getting started on a map of their own hometown. And I also hope expert mapmakers will chime in to tell us how we can improve our maps.

For more information and visuals,please visit:

> Wired