A one-dimensional map of NZ home ownership

By Aaron Schiff 30/01/2015

New Zealand is a long and skinny country, so I wondered if it’d be possible to visualise some geographic data on a one-dimensional map, ie only using latitude coordinates.

The next item in my Census challenge is household “tenure”, ie whether or not households own or rent their dwelling. This issue received a bit of press coverage recently. I’m also getting a bit bored of making regular maps of the Census data so I thought I’d try the 1-D map idea for this one.

The interactive chart below shows, for each meshblock, the proportion of households that own or partly own their dwelling, or where the dwelling is owned by a family trust, for 2013. So each circle is a meshblock and the proportion of home ownership is shown horizontally and the latitude of the meshblock is shown vertically. You can click on one or more region names at the right to filter the data.

One technical note: I have ‘jittered’ the data by adding a small amount of random noise to the home ownership percentage for each meshblock. This is because Stats NZ rounds Census meshblock results to the nearest multiple of 3, and in this visualisation that had the effect of creating strong vertical ‘bands’ at certain percentages, which I thought was distracting. The jittering doesn’t (in my opinion) change the overall picture.

To be honest I’m not sure if this is a very useful visualisation compared to a standard choropleth map, but it was interesting to make. I think you can see the distribution of home ownership is a bit different in larger cities compared to smaller ones. For example in Auckland there is a wide spread, whereas in regions with smaller cities (eg Gisborne), there is more of a cluster at higher percentages. For Auckland also you can see generally higher rates of ownership at the northern and southern extremes of the region compared to the centre.