Dasymetric mapping

Dasymetric mapping is a technique that is commonly used to improve population distribution maps. By default, population is displayed using census data, which is usually available for geographic units, such as census tracts whose boundaries don't necessarily reflect the actual distribution of the population. To be able to model population distribution better, Dasymetric mapping enables us to map population density relative to land use. For example, population counts that are organized by census tracts can be more accurately distributed by removing unpopulated areas, such as water bodies or vacant land, from the census tract areas.

In this recipe, we will use data about populated urban areas, as well as data about water bodies to refine our census tract population data.

Getting ready

To follow this exercise, please load the population data from census_wake2000_pop.shp (the file that we created in Chapter 2, Data Management), as well as the urban areas from urbanarea.shp, and...