"Topographic" map based on zillow-like data

Ok, like a lot of people I find it fascinating to browse Zillow and see the estimated values of my neighbour’s houses, and yes, I admit it, my friends. Another example of the little shock you get when data that was always technically public becomes truly public thanks to some new internet application.

Of course Zillow is adding to the data, by taking the public info (house sale figures, house size and features from county records and MLS) and applying algorithms to guess current values. However, they’re often quite innacurate. High for my house, way low for a number of others I checked. (Diane Feinstein’s new house, which just sold for $16 million, shows as only around 5 million. I wonder if she played some tricks to keep the value out of the records?)

Anyway, as this data becomes more available it would be nice to do other things with it. The idea I thought about was a something like a topographic map, so you could soar, Google Earth style, over “hills” of high value. Or plot other metrics like cost per square foot etc. Might also help people neighbourhood shop, and an interesting lesson in real estate capitalism.

Arbitrage, and data representation

There is an enormous opportunity in arbitraging the data that Zillow is showing so clearly, as long as the transactions' flow can be also streamlined. In my opinion a more popular representation would be not that of the more expensive properties, but the highest price *differentials* between two data sources, which would then of course point out the arbitrage points, or even markets.

We compared this for the

We compared this for the house we're considering the purchase of with the public records that are available for it. We noted that Zillow missed a sale that had been done on the house (important when one is using this data to determine appreciation relative to the cost of when the seller bought the house compared to what he's asking for it. Very powerful data as one is about to walk into negotiating a house deal, one of the major purchases most people ever face.


Have you seen the gapminder.org presentation? They do that kind of thing, but not in 3D. (and not for particular houses, but for demographics). Hopefully they'll learn the Google Earth API and do it in 3D.

The presentation is really funny and fun.

Click to start the video: http://video.google.com/videoplay?docid=7996617766640098677&q=gapminder

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