![population density map us at night population density map us at night](https://www.geogebra.org/resource/jUrXhbeX/FR0HzrmtHYWpZpSn/material-jUrXhbeX.png)
Meanwhile, dasymetric mapping is a method for mapping the distribution of population relative to land use or other ancillary data, such as building footprints, locations of roads, slope and elevation etc. Choropleth maps aggregate population data with administrative units (census tracts or block groups) whose boundaries do not always reflect the natural distribution of human populations. Population distributions are commonly displayed using choropleth maps of decennial census data. Familiarize the reader with the available global population distribution maps.Understand the concept of population distribution models.An example of local level population data is also described to demonstrate the application for small island countries of the Caribbean. In the following sections, the concept of population distribution model is explained and the current global gridded population datasets including Gridded Population of the World (GPW) database, Global Rural Urban Mapping Project (GRUMP), Land Scan, WorldPop, and HRSL population data are introduced.
![population density map us at night population density map us at night](https://i.redd.it/kdi05qrq65o31.png)
Since the 1990s, a spatially gridded population distribution map has also been developed by incorporating land use information and other ancillary data relevant to the distribution of population. Population distribution maps are mainly based on population count from census data which used administrative units as basic map units. Furthermore, census data are often only available at an aggregated level. However, collection of census data is a costly affair and resource intensive and it is normally completed once in a decade in most countries. Census data is the basis for governments for policy development, management and evaluation of development programs. They are also used as benchmark data for studying population changes (trend/direction), and are a key input for making population projections including gender, poverty, labor force, employment etc. It is the most reliable information for describing households, neighborhoods, cities, and countries. Census is the only consistent source for demographic data with a wide geographic scope.
![population density map us at night population density map us at night](https://i.pinimg.com/originals/45/d3/a5/45d3a567a0da5013902efe0dfc46a69d.jpg)
Rapid urbanization and population growth over the past decade has brought population distribution to forefront from a risk perspective. High resolution and spatially accurate data on population distribution are very important for disaster and risk management.