rebuilding a city from vacation photos

Dear Digital Archaeologist,

I'm so excited! I think I just caught a glimpse of your future work!

Many people take photos using digital cameras. Once they do, they need some way to share them, so over the last few years we've seen the rise of photo sharing sites like Flickr. Sometimes, we see people collaborate in a self-conscious way, like posting images from around San Diego during the wildfires and tying them to a map. Often, though, the coordination is unconscious, such as several people taking pictures of a historic landmark like the Statue of Liberty.

Now, for the first time, a group of researchers has written software that pulls together those pictures to build a three-dimensional representation of the landmark. The principles are fairly simple--they've been known to the technology of computer vision for some time--but there are some tricky parts like dealing with obscured images and calculating backwards to find out where the photographer was standing when taking the photo. The researchers are already talking about trying to recreate entire cities digitally using these uploaded photos.

Is this one of the things you do? Collating photos from our age, figuring out which ones occurred at about the same time, and using them to rebuild maps and three dimensional representations of our cities? Or is that just the start? Are you doing far more sophisticated analysis, such as using the sun's angle to tell time of day and then discerning daily traffic patterns based on where people stood when taking the images or having their images taken? Or discerning the chemical composition of our air by using photos to assemble an absorption spectrograph of sunlight passing through the atmosphere? Or estimating cloud cover based on shadows?

Of course, I've assumed those images survive intact. You might instead be so far in our future that you're happy to be able to assemble a single coherent image by combining the fragments from a thousand different disk sectors, trying to fill in the gaps in bit-rotted jpeg files.

In any case, I wish you well. I hope this message--or most of it, anyway--reaches you in good health. And if you're a grad student, best of luck to you on your thesis work.

Sincerely,
False Data

a nonrenewable resource

Dear Digital Archaeologist,

I spoke with one of your predecessors at dinner today. She's just finished her undergraduate degree and is planning to become a grad student. She's not a digital archaeologist, of course--she pieces together the past by physically digging up shells, potsherds, or other physical debris of past societies. Right now, she works for a company that does archeology for profit. As she explained it, we have laws which require anyone building something in an area of archaeological significance to, essentially, have an archaeologist available to tell them to stop their construction work if they find something important--say, shells or potsherds--long enough for the archaeologist to recover it. The laws have created the whole field of Cultural Resource Management and an opportunity for companies to hire archaeologists to be available at construction sites. In California, there are a lot of sites of archaeological significance--people have lived here for thousands of years--so they get a fair bit of work. I guess whether you think what they do is a net benefit to the economy or simply an extra cost on whoever's doing the building depends on how much you value the archeology they accomplish.

One of the things she said that stayed with me is that archaeological finds are a nonrenewable resource. She meant, of course, that once a bulldozer (a piece of earth moving equipment used in construction) destroys the site to put a building there, the things it destroys are gone forever, as is the chance to learn from them. That got me thinking about your job. Of course, you might need to rush in before whatever your modern equivalent of a bulldozer might be destroys files. In fact, you might need to rush in before knowledge of how to read a particular file format vanishes. But I wonder if archeology is a nonrenewable resource in a different sense.

You see, once you make a discovery--you find a piece of a puzzle--you need to assign meaning to it. You will need to interpret that new discovery in light of the context that surrounds you. Eventually, you will need to tell your colleagues about your interpretation. That moment, the moment where you decide what the new discovery means, is itself a nonrenewable resource. Once you have assigned meaning and told the world, that act changes the world, the surrounding context. People may accept your interpretation, or they may assign different meaning than the one you chose, but even if they they disagree with you they will also have altered that context in the process of disagreeing. The ripples from these decisions spread and interact.

Today, a man named James Cameron, a film maker, is trying to make one of those assignments of meaning. He claims to have found a container that held the skeletal remains of Jesus, a person of great religious significance who, according to religious texts, should not have had any skeletal remains in the first place. His claim is causing a great deal of controversy. No matter what people ultimately decide the container means, the repercussions will continue for a very long time, maybe forever.

digital archaeology

Gordon Bell at Microsoft has been creating some buzz for the MyLifeBits project, an effort to digitize essentially everything in his life. In a Scientific American article, he points out that you can buy a terabyte of storage today for $600, and within a decade you should have that same amount of storage in your cell phone (and four terabytes in a desktop machine.) Multiply that kind of storage capacity by the number of machines on the Internet and it got me thinking about what can start happening with the volume of information that expands to fill that kind of space.

Will there be digital archaeologists, people who sift through our society's discarded files and broken web links, carefully brushing away revisions and piecing together antiquated file formats? Will a team of grad students working on their PhDs a thousand, or two thousand, years from now be digging through old blog entries, still archived online in some remote descendant of the Wayback Machine or a copy of Google's backup tapes?

If so, welcome Digital Archaeologist. I'm honored you've paused to read this digital record. I might send you a letter from time to time, just to let you know how things are going here in your distant past. If I can help your research, so much the better. It's a strange world we live in now, one that's rapidly changing in directions that are not entirely clear. Perhaps by trying to explain it to you, I'll understand it better myself.