A 500 metre population grid using the Estimated Resident Populations (ERP) published annually, dated as at 30 June. Population estimates by Statistical Area 1s (SA1s) are used as an input to derive population grids. These estimates are not official statistics. They are derived as a customised dataset used to produce the population grids. This is one of three resolutions of the national statistical grid; 1 kilometre, 500 metres and 250 metres, where the distance is the length of one side of the square grid cell. The Estimated Resident Population (ERP) by Statistical Area 1 (SA1), rounded to the nearest 10, was proportionally divided between private and some non-private dwelling point locations from the Stats NZ Statistical Location Register. The dwellings were spatially joined to the SA1 to calculate the number of dwellings within each SA1. The SA1 ERP divided by the number of dwellings gave the number of people per dwelling for each SA1. The people per dwelling was spatially joined back to the dwelling dataset then spatially joined to the grid with the option chosen to sum the dwelling population within each grid cell. The estimated resident population of an area in New Zealand is an estimate of all people who usually live in that area at a given date. It includes all residents present in New Zealand and counted by the census, residents who are temporarily elsewhere in New Zealand and counted by the census, residents who are temporarily overseas (who are not included in the census), and an adjustment for residents missed or counted more than once by the census (net census undercount). Visitors from elsewhere in New Zealand and from overseas are excluded. Population estimates by SA1s are used as an input to derive population grids. These estimates are not official statistics. They’re derived as a customised dataset used to produce the population grids. Population estimates from 2022 and 2023 use 2018 Census data and will be revised in 2025, after 2023 Census data is available. Changes to the ERP figures for a grid cell between years, are due to either: estimated change to the residential population for an area or the following methodological factors may also increase or decrease the population estimate assigned to each grid cell; five yearly changes to the SA1 boundaries to which the ERP figures are assigned. Between 2022 and 2023, non populated areas were separated from some SA1s, resulting in fewer grid cells being populated. Changes to SA1 boundaries are designed to ensure they incorporate areas of new development, maintain the urban-rural delineation, and meet population criteria. changes to the dwelling dataset. This is the production version of a new dataset published in November 2023. The prototype version was released in October 2022 for feedback. Since the November 2023 release, population estimate field names have been updated to remove acronyms and population estimates have been reduced to two decimal places.
