Quantifying the Sustainability of Urban Growth and Form through Time
An Algorithmic Analysis of a City’s Development
Idaho State University Participants
Jared Ogle, M.S. and Donna Delparte, PhD.
Partners and Affilation
Hannah Sanger - City of Pocatello
To discern the sustainability of Pocatello’s past growth and current urban form, so that policy makers can make data based decision for planning future growth and managing ecosystem services, various data reflecting changes in urban growth and metrics have been developed to quantify change in sustainability over time in Pocatello
To accomplish this, we have coordinated with members of the city and county to collect data depicting present day Pocatello, and with the help of aerial photography reconstructed urban form: built extent, building footprints, and transportation infrastructure of Pocatello on a decadal basis from 1941 until today. Utilizing this data along with population and household data we have constructed algorithms that quantify various aspects of sustainability and form, giving an overall sustainability score for the city for every decade studied. The output from these show various trajectories of growth over the past 75 years and how changes in urban form have affected the sustainability of Pocatello.
An understanding of how past growth choices effect the sustainability of Pocatello and how its built footprint utilizes one of the most important ecosystem resources, the land itself, can give decision makers in Pocatello the power to evaluate how changes in the cities growth utilize natural capital. Aspects of the city such as, lot size, dwelling unit types, which are all effected by city policy choices can show how past policy has effected the cities sustainability. Beyond Pocatello, the python-based algorithms can be utilized by other cities’ planners and policy-makers with data and layers available to almost every municipality.
Figure 1 - Intersection density is indicative of block size and has been shown to have a positive correlation to population. As the city of Pocatello has grown away from old town seen mostly in red and orange, density of intersections has decreased. Table 1. Indices for density, compactness, and clustering, as well as, the composite metric of the three, overall sustainability of form. Higher scores indicate more sustainable metrics, and all have been indexed relative to the present day