Dot-Density Maps In R

Paul Campbell shows how to build a dot density map in R:

To get me started I invested in the expert guidance of data-visualiser-extraordinaire Nathan Yau, aka Flowing Data. Nathan has a whole host of tutorials on how to make really great visualisations in R (including a brand new course focused on mapping) and thankfully one of them deals with how to plot dot density using base R.

Now with a better understanding of the task at hand, I needed to find the required ethnicity data and shapefiles. I recently saw a video of Amelia McNamara’s great talk at the OpenVis Conference titled ‘How spatial polygons shape our world’. The .shp file really is a glorious thing and it seems that the spatial polygon makers are the unsung heros of the datavis world, so a big round of applause for all those guys is in order.

Anyway, I digress. Luckily for me, the good folks over at the London DataStore have a vast array of Shapefiles that go from Borough level all the way down to Super Output Area level. I’m going to use the Output Areas as the boundaries for the dots and the much broader Borough boundaries for ploting area labels and borders.

The ethnic group data itself was sourced from the Nomis website which has a handy 2011 Census table finder tool where you can easily download an Ethnic Group csv file for London output areas. Vamonos.

I’m going to give this a second reading; it’s a great example of how to go from functional to beautiful.  H/T David Smith

Related Posts

Beware Multi-Assignment dplyr::mutate() Statements

John Mount hits on an issue when using dplyr backed by a database in R: Notice the above gives an incorrect result: all of the x_i columns are identical, and all of the y_i columns are identical. I am not saying the above code is in any way desirable (though something like it does arise naturally in certain test […]

Read More

“Pretty But Useless” Visuals

I continue my dashboard visualization series with a bit of an extended rant: The best use of a pie chart is to show a simple share of a static total.  Here, we can see that Daredevil has almost half of the critics’ reviews, and that The Punisher and Jessica Jones are split. This simple pie […]

Read More

Categories

June 2017
MTWTFSS
« May Jul »
 1234
567891011
12131415161718
19202122232425
2627282930