And finally townships are mostly rural, except when they are immediately adjacent to cities and boroughs.Īnother example that demonstrates how population density shows how people live is how it reflects family size. Boroughs represent an urban development usually smaller than cities (but no less densely populated, as the table below shows).
As noted above, cities generally have the largest relative populations in their counties and likewise, the largest population densities. Rural living, whether on farms or in forested landscapes or even desert areas, feature the maximum distances between dwellings.Ī similar, but not identical, distinction that describes where people live is the difference between the three types of municipalities in Pennsylvania: cities, boroughs and townships. The key attraction for those leaving cities and smaller towns for suburban housing developments starting in the 1950s was the separation between dwelling units while keeping the neighborhood-based lifestyle. So do city blocks of row homes with small to non-existant backyards. Taller residential buildings that are more likely to be found in larger cities reduce that distance tremendously. Census tracts are of widely varying sizes because they contain relatively consistent populations.įor one example of its ability to describe where people live, population density measures the relative ground distance between people's residences. An example of the latter are "census tracts," devised by the US Bureau of the Census decades ago to provide an effective framework for the redistricting of US House of Representatives every 10 years and adapted for many other uses since then. Population density is calculated by first defining an area, whether it is outlined by political boundaries or by boundaries defined for other reasons. It can be used as a factor to try to explain a wide range of other population measures, such as income, politics and access to healthcare. It can be used to differentiate urban vs. Accessed DAY MONTH YEAR.Population density is a measure that combines several facts about where and how people live. Source imagery for HRSL © 2016 DigitalGlobe. To reference this data, please use the following citation: Facebook Connectivity Lab and Center for International Earth Science Information Network - CIESIN - Columbia University. This preserves the relative population totals across administrative units while matching the UN total.
The resulting adjustment factor is multiplied by each administrative unit census value for the target year. The UN estimate for a given country (or state/territory) is divided by the total census estimate of population for the given country. For more information about the methodology used to create our high resolution population density maps and the demographic distributions, please visit: įor information about how to use HDX to access these datasets, please visit: Īdjustments to match the census population with the UN estimates are applied at the national level. The resulting maps are the most detailed and actionable tools available for aid and research organizations. Then we work with our partners at Columbia University to overlay general population estimates based on publicly available census data and other population statistics. To create our high-resolution maps, we use machine learning techniques to identify buildings from commercially available satellite images. Creative Commons Attribution International