An Evaluation of Land Parcel-Weighted Areal Interpolation in Small Areas

Kyle Reese-Cassal, State of Washington

Small-area population estimates for user-defined boundaries require that administrative areal units be split and re-aggregated. This process of allocation requires a detailed understanding of the distribution of attributes at a greater scale than the finest areal unit. Rather than working with the assumption that attributes are distributed uniformly across areal units, accuracy can be improved by creating a population surface based on additional sources of data related to the true population distribution. Many complex strategies have been developed to estimate population distribution based on land use and land cover classification systems. A more simplistic strategy is accessible to applied demographers. Administrative data, such as land parcels, can be utilized to geo-reference actual housing units, which can then be transformed into a population surface. This paper describes the process of creating a population surface from land parcels and then tests this method of attribute distribution against the more common method of area-weighted areal allocation.