Visualizing 3-dimensional spaces using flat images

When I first saw the TED demo of PhotoSynth by co-creator Blaise Aguera y Arcas, I was awed and intrigued (not at that unusual).

But, as with so many novel ideas, I didn't really grasp what it was about, didn't fully understand it, didn't know what to do with it at the time.

 The idea of simulating 3-dimensional movement using a database of 2-D images intrigued me.

 To me it was a novelty, for sure. I imagined it as a way to archive history -- not just  to simulate 3-dimensional spaces, but to travel backwards in time.

 Virtual time travel -- maybe there's something to that idea.  Or maybe not. Forensics? Crime scene investigation? Environmental monitoring?

 That was before I carried a digital camera around in my pocket, before I posted so many images to Picasaweb that I have a hard time managing them, before I became a regular user of a social network on which people are posting new images several times a day.

 And then I began to appreciate what PhotoSynth could do with "current" photo.  After all, time is just another dimension to consider: all the photos in any database are in a sense "historical" photos.  Each photo represents a point in time, a point in 3-dimensional space, a vector (directional view), a magnification factor, etc.

 We can intentionally attend to certain dimensions and filter-out others. We can create applications that assist us in filtering-out or enhancing certain dimensions. And we can index or otherwise annotate those dimensions with metadata ("Africa trip", "Capetown", "Eilene", etc.)