1997 / 1997
Probably the two most important English economic indicators, for the common citizenry at least, are median average house price and median average household income (The 'median' is important here, for a brief explanation see here - in essence it's the average that better reflects the common lot.). By combining these two we can derive a ratio, of house-incomes to house-prices (HI / HP), which says a lot about the state of the English economy. I wanted to track the changes of this ratio using the most recent data available (1997-2012) and, to dramatically emphasize the change, reflect this by warping a map of the English regions to make the areas reflect the change in this ratio since 1997. What this shows is a staggering reduction in house-purchasing power over a mere fifteen years, not even a full generation. Across England the HI / HP has halved during this period, but many regions, particularly the south-east, have seen far greater rises (e.g. Brighton, where houses in 2012 were, on average, 9.5 times the household incomes of the city). This trend represents nothing less than the economic disenfranchisement of present and future generations, a literal and figurative generational land-grab.
The large map below shows the English regions, with their areas warped so as to reflect the reduction, relative to 1997, of the house purchasing power of the median average household wage. You can click on a region to highlight it (right map). The slider at the bottom allows you to change the year, or you can press the animate button. To turn the area warping off press 'warp off'.
Here we superimpose a shrunken regional map, adjusting for the change in house buying power since 1997. The map is scaled by the ratio HI / HP for the current year divided by that of 1997.
D3 did the heavy-lifting with it's wonderful topographic map extensions. Shawn Allen's d3-cartogram is a very cool little implementation of James A. Dougenik, Nicholas R. Chrisman and Duane R. Niemeyer's cartogramic algorithm. The docs are a little on the sparse side but it was nice to have. Generally cartograms preserve the total original area but I wanted that to shrink with the HI->HP ratio, which required hacking the source (yay for open-source software). I used the Dimple library for the chart but had to fight it a little to get what I wanted. Once again I'm reminded that D3's great boon is to enable one to break free of such constraints. Thanks to all.