Population density & diversity in New Zealand

Stats NZ has developed a series of interactive maps, focusing on two aspects of 2018 Census data – population density and ethnic diversity.

These maps can help answer questions about the population density of New Zealand's suburbs, towns and cities, as well as the ethnic diversity within these places. They help us see where ethnic populations are living closer together, forming their own communities (lower ethnic diversity), and where many different ethnic groups are living together, to create higher ethnic diversity.

We have presented the data at the statistical area 1 (SA1) level, using publicly available, confidentialised data. SA1 is the smallest geographic area that population data from the 2018 Census data is available for publicly.

Note: These maps are not designed to be detailed analytical tools; rather they show spatial patterns of people within different ethnic groups.

How the map works

In order to show the two variables of population density and ethnic diversity on a single map, we have used a mapping technique called multivariate  dot density  mapping.

Dots representing a proportion of the population are placed randomly within the SA1 geographic area. As the placement of the dots is random, dot location does not correspond to an actual location.

The more dots there are in an area, the larger the population, and the closer together the dots are, the greater the population density. Each ethnic group present in an SA1 is represented by a different coloured dot. The more of a colour there is in an area, the higher the number of responses there were by people identifying with that ethnic group.

As the maps zoom in and out, the number of dots in an SA1 will change so that the optimum view is maintained. At the finest scale, a single dot represents no fewer than three individual census responses, and will represent more responses when zoomed out (for example, one dot may represent 10 responses, 50 responses, or more).

The ethnic groups shown on the map

Stats NZ groups the population into broad ethnic groupings, with the five most common groupings presented here: Asian, European, Māori, Middle Eastern/Latin American/African (MELAA), and Pacific peoples (see  Ethnicity  for more information). Check the key on each map to see which dot colour represents which ethnicity.

The dynamic nature of the maps

We have presented four maps, focusing on the four metropolitan areas of Auckland, Wellington, Christchurch, and Dunedin. As noted earlier, these maps are interactive, and as well as zooming in or out, you can move them around to explore other nearby areas. Alternatively, you can click on the magnifying glass symbol at the top left of the map and type the name of a suburb, towns and city into the search bar that will pop up.

Note: The maps work best in Google Chrome, Mozilla Firefox and Safari (Mac), and you'll have the best experience on a computer or tablet.

About the 2018 Census dataset

We combined data from the census forms with administrative data to create the 2018 Census dataset, which meets Stats NZ’s quality criteria for population structure information.

We added real data about real people to the dataset where we were confident the people should be counted but hadn’t completed a census form. We also used data from the 2013 Census and administrative sources and statistical imputation methods to fill in some missing characteristics of people and dwellings.

 Data quality for 2018 Census  provides more information on the quality of the 2018 Census data.

An independent panel of experts has assessed the quality of the 2018 Census dataset. The panel has endorsed Stats NZ’s overall methods and concluded that the use of government administrative records has improved the coverage of key variables such as age, sex, ethnicity, and place. The panel’s  Initial Report of the 2018 Census External Data Quality Panel (September 2019) , assessed the methodologies used by Stats NZ to produce the final dataset, as well as the quality of some of the key variables. Its second report  2018 Census External Data Quality Panel: 

 Assessment of variables (December 2019)  assessed an additional 31 variables. In its third report,  Final report of the 2018 Census External Data Quality Panel (February 2020) , the panel made 24 recommendations, several relating to preparations for the 2023 Census. Along with this report, the panel, supported by Stats NZ, produced a series of graphs summarising the sources of data for key 2018 Census individual variables,  2018 Census External Data Quality Panel: Data sources for key 2018 Census individual variables .

The  Quick guide to the 2018 Census  outlines the key changes we introduced as we prepared for the 2018 Census, and the changes we made once collection was complete.

The geographic boundaries are as at 1 January 2018. See  Statistical standard for geographic areas 2018 .

Definitions and metadata

The ethnicity variable is rated as high quality.  Information by variable  has more information (e.g. definitions and data quality). Where a person reported more than one ethnic group, they were counted in each applicable group.

 2018 Census – DataInfo+  provides information about methods, and related metadata.

 Data quality ratings for 2018 Census variables  provides information on data quality ratings.