2011 Census Map

The choropleth map and accompaniments below use data compiled by the Office for National Statistics. This data concerns the 2011 census for England and Wales (see also). The map itself was also kindly supplied by the ONS (though I have modified it slightly, removing Scotland for instance).

Any one of 89 different variables can be encoded in the map using the bottom drop-down menu and the values in the table can be sorted alphabetically or in ascending or descending order.

The map has two options for colour scales: green to red (with a blue background) and blue to red (with a grey background). While personally I find the former more aesthetically pleasing, the latter is aimed at providing better support for those who suffer from colour vision deficiencies (please let me know if you still have problems). Both colour scales come from the excellent ColorBrewer2 website.

The actual colour encoding is based on the principles of a box plot. Regions in the midspread are coloured yellow while those within 1.5 times the midspread below and above the midspread are coloured light green/blue and light red, respectively. Any outliers beyond these bounds are coloured dark green/blue and dark red.

Clicking on any table entry or the corresponding region on the map (the latter option may not work in some mobile browsers) will highlight both and enable the tracking of that region if you change the variable encoded in the map or the ordering of the table entries. It also adds a pair of black markers to the key at the bottom. The vertical marker highlights the value encoded directly along the horizontal axis tied to the key. The horizontal marker gives an indication of where that value appears in the cumulative distribution of all values for the variable. That is, the region with the lowest value for a given variable will have a marker spanning the base of the boxes in the key while the marker for the region with the highest value will appear at the top. All other regions will have a horizontal marker somewhere in between. Where many regions share the exact same value (the data is only given to one decimal place) this horizontal marker will appear thicker.

Finally, the boxes in the key also act as simple filter controls. Clicking on any box sets all regions that aren't that colour to white and removes their entries from the table. Click on the same box again to undo this filtering.