I did want to take a moment and comment upon how the science fiction field's social infrastructure contributed to the genesis of the work of collaborative cartography presented here at this blog.
First of all, my general attitude toward disaster response was nurtured by Patrick and Teresa Nielsen Hayden's blog Making Light, with its intelligent and fertile comment sections, where I had much of my early Katrina commentary. A DOS attack on their server aimed at another site shut down their site at just the time the levee breaks were being reported. So I did my own post, New Orleans Levee Break(s) Before and After (originally phrased in the singular). Patrick and Teresa are longtime science fiction fanzine fans and also have been my friends for decades. They both work at the science fiction publishing house, Tor Books, where my husband David Hartwell also works. (I shouldn't forget to acknowledge my ovely wife David, without whom none of this is possible, who has put up with me spending all this time on the Katrina Maps project.)
Once the levee break piece was posted, it seemed to me after a look around that I had the only levee Before & After shots available on the web. So I wrote a note to my friend Cory Doctorow using the BoingBoing submit-a-site page telling him about it. (Further connections: Tor publishes Cory; Patrick is his editor. When I was pregnant with my first child, Cory jokingly suggested we name him Darth; we chose Peter instead.) Xeni, who was doing most of the Katrina coverage there, picked it up and sent me a band of useful techies. (Also, Ned Sublette, providing some of BoingBoing's other early Katrina coverage, is the significant other of fantasy writer Constance Ash.)
From there, the whole thing took on a life of it's own.
I suppose I should add that New Orleans hosted both a World Science Fiction Convention and a World Fantasy Convention. Nolacon, the Worldcon in New Orleans, had a number of programming disasters, but New Orleans is (or was) such a great city, that the very charisma of the city saved the convention. Who cared if the infrastructure of the convention had fallen apart. The WorldCon was in New Orleans! We had a great time!
And then there's Jim MacDonald's check-in page and Gary Farber (who was once a Worldcon Chair; and who lived on P & T's sofa for a while; and then in an apartment with a roomate who borrowed some of my furniture). This is a tightly knit little tribe you see. Many fewer degrees of separation. We liked New Orleans.
We pay back.
(I'm sure I've left some science fiction people out. By all means, rush forward and claim credit where credit is due!)