The Wrong Side of my Car

The blog that wants to go obsolete

Census 2018: population density

Last year (2018) there was a census, and after a long and turbulent process, the data is now gradually being released to the public.

One of the data tables already available is about population by Statistical Area 2 (formerly known as Area Units). In general over here these are areas of about a kilometre across, with a few thousands of people living in them.

The estimated population was given for the previous census years as well (2006 and 2013) so of course we are going to make a GIF. *1

We can also show the change from 2013 to 2018 directly:

A few things I noticed:

• The very abrupt change between the high density in the CBD (over 10,000/km²) and surrounding suburbs (generally below 4000/km²). Normally in a growing city you would expect that high density area to feather out, similarly to how the suburbs are spreading into the surrounding countryside.

• The growth in South Auckland, which is now more densely populated than the so-called high density suburbs on the isthmus.

• The start of a new satellite town in the north west. Unfortunately, just like the older ones the only transport serving it is road based (there are no passenger trains on that railway). Maybe it is not too late to plan a town which is actually pleasant to live in even for people who wander past their front fence without a car.

• The lack of population around most of the route of the Northern Express. This is the swamp of Akoranga, the parking lot and golf course of Smales Farm, and the ‘commercial’ areas of Wairau Park *2 and Rosedale.

• The lack of population in New Lynn (which is an important public transport node). There is probably a similar ‘hole’ in Takapuna but it is not as neatly captured by a statistical area.

• The loss of population in some parts of Grafton and Parnell. Maybe an artefact of how students are counted.

There is always a compromise between avoiding too large thresholds, and still being able to match colors with the legend.

As an alternative for just using a lot of colors, I tried with just 3 colors, and mixing them using halftone patterns. These 3 colors (solid for 0, 1000 and 5000) are easy to recognise. In between we can vary the pattern continuously to avoid large thresholds.

Update: since the meshblock data set is out, we can repeat this exercise per meshblock:

You can see a few details here, for example the area around the proposed tram *3 line on Dominion Road doesn’t have the dense settlements like the ones around Sandringham Road or Manukau Road. Or you can see Hobsonville Point pop up in 2018.

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