neonascent

As I’ve mentioned elsewhere, I’m reading spatial theorist Michel de Certeau for an account of spatial practices. De Certeau emphasises the inadequacy and restrictiveness of abstract representations of place as administered by authority (land owners, city planners, architects), and exposes the everyday lived experience of space which is enacted beyond it. The abstract conception of place is held by those with established, demarcated territory, who attempt to control and survey it. He calls this action Strategic. In contrast to this is the Tactical; the everyday poaching of space as we move through the city, working subtly and intuitively against the logic of the Strategic model, while jaywalking or short-cutting across the grass or squatting.

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In a similar vein to the image-matching against point-clouds that was demonstrated in the Bing Maps TED talk, PhotoCity is aiming to progressively construct a 3D scan of the world. To this end they have released a free iPhone app that displays current scans, and encourages users to compete to fill in gaps in the scans. Currently there is a limited number of locations available to add to, but you may start your own “seeds”, which will create new areas to improve. I’m thinking of committing to a University of New South Wales seed – any helpers?

Edit: Still waiting for my building seed to be processed from this morning. The project is very new, so hopefully the delay is because they have a backlog, and not because they have abandoned processing new locations all together.

Earlier this year, the UK-based Prospect magazine featured an article by Stewart Brand (publisher of the Whole Earth Catalogue) entitled “How slums can save the planet”.

The article looks at lessons that can be learned from the organic arrangement and efficient reuse of slums, as well as making the controversial claim that cities are the actually green. As architect Peter Calthorpe suggests:

“The city is the most environmentally benign form of human settlement. Each city dweller consumes less land, less energy, less water, and produces less pollution than his counterpart in settlements of lower densities.”

It’s an interesting polemic to conventional wisdom, although it is hard to know how much it relies on ignoring the rural and overseas industries working to provide for the cities.

For slums in particular, there are some green practices imposed by needs:

Squatter cities are also unexpectedly green. They have maximum density—1m people per square mile in some areas of Mumbai—and have minimum energy and material use. People get around by foot, bicycle, rickshaw, or the universal shared taxi.

and

…in most slums recycling is literally a way of life. The Dharavi slum in Mumbai has 400 recycling units and 30,000 ragpickers. Six thousand tons of rubbish are sorted every day.

As some of the post comments point out, Brand has a particularly romantic idea of the transformative element of living in the cities. While he acknowledges that cities “concentrate crime, pollution, disease and injustice as much as business, innovation, education and entertainment”, he also sees new residents as naturally “progress[ing] from hick to metropolitan to cosmopolitan”, with everything that entails.

If nothing else, it is an interesting call to investigate City Planning practices against spaces defined by a lack of planning. But as always a system that develops as highly responsive to specific needs – such as a shanty town – may have difficulty incorporating less immediate needs such as protection from Earthquake or fire risk.

Posting a little late, via Beyond the Beyond: A Museum of London Augmented Reality iPhone app that gives you access to a library of historical, geotagged images. While the screenshots have been meticulously constructed to be perfectly registered, having seen the level of precision mobile AR is up to at the moment this is going to take some work to reproduce. The results look a lot like a PhotoSynth match up of two images, which is something of a foreshadowing of the near future when these geotagged images will be more intelligently plugged into a point-cloud of the persistent architecture (the corners and cornices of those old buildings that haven’t changed for decades).

For the moment it’s a reminder of the growing body of located media, along with digitisation and making machine-legible of formerly fuzzy content of our world.

I’ve discussed (with examples of a reconstruction from Newcastle) some of the technologies for doing 3D reconstruction. PhotoSynth is by far the easiest way to get into this, but it is not as powerful as some other options.

For example, PMVS2 allows you to reconstruct a detailed 3D point-cloud, and takes as its input a collection of images, and parameters about the position and intrinsics of the cameras.

Helpfully, the latest version of SynthExport allows you to export the camera parameters from your PhotoSynth, for use in the more powerful reconstruction. I have written a javascript form that generates the two input files needed for the PMVS2 pipeline.

Edit: The focal length is now being calculated correctly, but there is a problem with the data – it is not processing correctly. The rotation matrix calculations are from a great matrix calculator and seem to be working fine, and the translation are just simply brought over directly from PhotoSynth. I don’t have a good way to plot these points myself, but I might ask a colleague to give it a try for me. Obviously I’m keen to get this up and running ASAP, so please comment for feedback and revision suggestions!

Edit: I am working on getting the correct format for piping PhotoSynths to PMVS.

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