![]() Yes that’s slightly arbitrary and not ideal for cities with dense cores on coastlines, but at least I’ve been consistent. While these boundaries are not determined in the exactly the same way, one good thing about population-weighted density is that parcels of land that have very little population don’t have much impact on the overall result (because their low population has little weighting).įor each city, I’ve included every grid cell where the centroid of that cell is within the defined boundaries of the city. These methodologies tend to exclude satellite towns of cities (less so in New Zealand and Canada). For Canada I’ve used Population Centre, and for New Zealand I’ve used Urban Areas. For Europe I’ve used 2011 Morphological Urban Areas, which have fairly similar rules for boundaries. For Australia I’ve used Urban Centre boundaries, which attempt to include contiguous urbanised areas (read the full definition). The second challenge with these calculations is a definition of the city limits. This is could count against a city like Sydney with a large harbour. The more watery cells, the lower the calculated density. You can see that many of the grid cells that include significant amounts of water show a lower density, when it fact the population of those cells are contained within the non-water parts of the grid cell. For example, here is a density map around Sydney harbour (where light green is lower density, dark green is medium density and red is higher density): It’s not perfect, particularly for cities with small footprints. Some measures of density exclude all non-residential land, but the square kilometre grid approach means that partially populated grid parcels are counted, and many of these parcels will include non-residential land, and possibly even large amounts of water. I’ve also generated my own kilometre population grids for Canadian and New Zealand cities by proportionally summing populations of the smallest census parcels available. To overcome the issue of different parcel sizes, I’ve used kilometre grid population data that is now available for both Europe and Australia. As I’ve shown previously, the size of the parcels used makes a big difference in the calculation of population-weighted density, which makes comparing cities difficult internationally. Rather than divide the total population of a city by the entire city area (which usually includes large amounts of sparsely populated land), population weighted density is a weighted average of population density of all the parcels that make up the city. Why Population Weighted Density?Īs discussed in previous posts, population-weighted density attempts to measure the density at which the average city resident lives. ![]() It also shows a breakdown of the densities at which these cities’ residents live, and includes a set of density maps with identical scale and density shading. This post calculates the population-weighted density of 53 Australian, European, and Canadian cities with a population over 1 million, plus the three largest New Zealand cities (only Auckland is over 1 million population). Just how much denser are European cities compared to Australian cities? What about Canadian and New Zealand cities? And does Australian style suburbia exist in European cities?
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