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Frequently Asked Questions
What am I looking at?
Every person counted in the 2011 census of England, Wales and Northern Ireland is represented as a dot on this map – all 57,886,775 of them. Each dot’s location is near to a person’s usual residence, but the locations are not exact; public census results only report location to within a small area, usually containing a few hundred people. These are called ‘output areas’ in England and Wales, and ‘small areas’ in Northern Ireland. To create the map, I randomly place each person within their respective area. The colour of the dot reflects the person’s ethnicity as reported on the census.
Can I use this map?
Yes, with attribution. Consider it CC BY 3.0 licensed. The data is from the 2011 Census, via ONS (England & Wales) and NISRA (Northern Ireland) and you should cite them too, as the original source of the data.
What happened to Scotland?
The UK actually has three coordinated censuses, devolved in Scotland (to NRS, National Records of Scotland) and in Northern Ireland (to NISRA, the Northern Ireland Statistics & Research Agency). As of September 2013, NRS has not yet released ethnicity data from the census.
Why are there people living in Hyde Park, at Heathrow Airport, etc
The census data only show that a person lives in particular statistical area, not exactly where they live. Some statistical areas include within their boundaries parks, lakes, airports, etc. Since I randomly locate each dot, it may well end up on one of these features. Hopefully in the next version I will use additional data on these locations to tidy up such anomalies.
Where are the place names for Leicester, Newcastle, etc?
Missing. I’m using third-party mapping tiles for the background, but they seem to have made some mysterious choices about which place names to include and exclude in the UK. If you know of a better set of tiles, please let me know.
Is this directly comparable with Dustin Cable’s US Racial Dot Map?
No, for at least two reasons. First, while I’ve tried to retain the look of Dustin’s map, I used a different module to draw points, which means the exact appearance varies from his map, particularly when zoomed out. Second, US race groups and UK ethnic groups are hard enough to define as it is (there’s a book on that), and probably aren’t directly comparable.
Okay, well what is ethnicity anyway? Why is it ethnicity in the UK and race in the US?
I don’t know why the UK asks ‘What is your ethnic group?’ while the US asks ‘What is Person 1’s race?’ If you’re a census historian, and know the answer to that question, I’d love to hear it. (Actually if you’re a census historian, then I’d love to meet you, full stop.)
Can you tell me more about ethnicity in the UK?
No. But these people probably can.
What data sources did you use?
For England and Wales ethnicity, I used KS201EW at the level of output areas, available from the ONS Nomis website. For England and Wales output area boundaries, I used ONS shapefiles (full, clipped).
For Northern Ireland ethnicity, I used KS201NI at the level of small areas, available from the NISRA NINIS website. NISRA doesn’t group ethnicities in quite the same way as ONS, so I created groups for White (White, Irish Traveller), Asian (Chinese, Indian, Pakistani, Bangladeshi, Other Asian) and Black (Black Caribbean, Black African, Black other). I believe this is consistent with the ONS data. For Northern Ireland small area boundaries, I used NISRA shapefiles.
This map is The Truth, right?
No, this map, like any map, is just one way of visualising a complex reality. I made all kinds of choices about how to arrange, color and display the dots, and these choices may well significantly affect your perception of the data presented. Caveat emptor!
If they cancel the census, will you be able to produce a map like this in 2021?
Can I use these images for my blog/article/t-shirt/coffee mug/etc?
Sure, as long as you credit me and link them back to projects.andrewwhitby.com/uk-ethnicity-map (except for the t-shirt and coffee mug – then just send me one in lieu of a link!)
Can I get a copy of your code?
Of course. It’s on github.
Who else deserves credit?
Dustin A. Cable produced the US map that inspired me, and provided the code on which I based my map. His work, in turn, was based on a project by Brandon Martin-Anderson from the MIT Media Lab. The reference tiles showing roads and placenames are from Stamen Design based on OpenStreetMap data.
The code is based on Dustin’s (see his Methodology), although I substantially rewrote his code to make it more general and, hopefully, quite a bit more reuseable.
The key differences are that:
- All the project-specific settings are in settings.py, so it’s easy to adapt to different datasets.
- I added a processing stage to merge attributes (here, ethnicity) into the shapefiles, since these usually come separately.
- I automatically translate boundaries, if necessary, to GDS-84, since the UK does not use this by default (unlike the US).
- Instead of using Processing for the image output, I use Python with the PIL library. I had some trouble with command-line Processing, and it seemed unnecessary to add an extra language/interpreter when Python has perfectly good image libraries.
- I have included a template client, and a script to automatically generate a ready-to-deploy index.html, including nice features like an HTML-based legend (rather than an image).
Since my website is hosted on wordpress.com, I have hosted the map on Amazon S3 cloud storage, which is a fairly straightforward process, for a server-static/entirely-client-side application like this.