Chapter 2 Background

This set of lecture notes was created for the purpose of teaching QTM 3605, Quantative Analysis of Structural Injustice, at Babson College. It specifically considers the use of GIS in structural injustice applications, such as visualizing disparities between groups or joining spatial data for use with cross-sectional or panel data. GIS, which stands for Geographic Information Systems, is an environment for the development, management, visualization, and analysis of spatial data. GIS software is a powerful tool for policymakers to consider the inherent variation in geographic data. If we consider the United States, the 50 states, District of Columbia, and its territories are extremely different in their beliefs, behaviors, policies, and patterns of tendencies. To be able to both visualize these variations and to consider it in analytical results, such as regression analysis, is crucial to the policy-making process.

This chapter introduces the student to the basics of GIS. The next two chapters will introduce students to concepts in the application of GIS mapping in visualizing disparities in two open-source contexts using QGIS and R.

2.1 What is GIS?

ESRI, the company which developed AcsGIS software, describes GIS as:

“A framework for gathering, managing, and analyzing data rooted in the science of geography. It analyzes spatial location and organizes layers of information into visualizations using maps and 3D scenes. With this unique capability, GIS reveals deeper insights into data, such as patterns, relationships, and situations – helping users make smarter decisions.” ESRI, developer of ArcGIS

Beyond the simplified definition we see, the development and use of maps and mapping software is crucial to our understanding of the world. There are numerous considerations for the analysis of spatial data. For example, the storage of visual data is a complicated task; spreadsheets and tables cannot handle this type of data. The GIS environment is primarily a database that allows for the storage, aggregation, and retrieval of spatial data. Prior to visualizing or analyzing spatial data, we have to consider the coordinate system used, the data structure, and the use of multiple types of data on a single assignment. That is why GIS is such a powerful tool: Without it, we would be left with drawing maps by hand and joining spatial data with cross-sectional data manually.

2.2 What is GIS useful for?

GIS data is useful for many things, such as:

  • Mapping where things are

  • Mapping quantities

  • Mapping Densities

  • Finding what features are located somewhere (i.e., Google Maps Street View)

  • Finding what is nearby (i.e., within a zone or distance)

  • Mapping changes over time

GIS is used across industries, such as supply chain management, insurance, forestry, urban planning, retail banking, health and human services, journalism, and marketing and strategy. It is just as useful for policy makers as it is for business people. Environmental scientists use it to map out water temperatures and lobster catches. Marketers use it to think about location of retail stores relative to competitors. Insurance companies use it to map out flood zones. Congress workers use it to create election maps. One of the latest industry to make incredible use of GIS software is journalism, where the confluence of big data in geography has intersected with the need to bring detailed and crucial information to the public.

2.3 GIS for the Public Good

Of note, journalists have employed GIS visualizations greatly to enhance how data is disseminated to the public at large. Whether it is for the use of chloropheth maps to show variation across geographic locations or for the use of providing variation in densities of a continuous running variable, the examples are numerous. Some of the most important maps in the last several years are the depiction of COVID-related numbers. For example, the New York Times used GIS tools to depict COVID vaccine rollout in 2021. Another major example is the use of maps in election news. For example, The New York Times used GIS tools to produce an “extremely detailed map” of voting results across the country.

There have been scholarly work that have just as well impacted public perception. For example, scholars have digitized the redlining maps used by HOLC for the purposes of home loans beginning in the 1930’s. For a long time, these maps were stored as hard copies, but through hard work, these scholars have made the maps, its data, and its GIS data available for the world to use.

The government have used GIS in many ways, given that the collection of economic, socioeconomic, and demographic data from various areas of the country is a public good that many institutions rely upon. For example, the US Department of Education has maps of schools and school districts and the White House uses infrastructure data maps to develop policy.

Overall, we have made great progress to use maps to shine lights on disparities in society and in ways that benefit the public good. These maps affect public perception of the news and make obvious the variation in beliefs, tendencies, and patterns across contexts. And they color the way we feel about inequality and system injustice. But the use of GIs data can also be complicated for the beginner. The the following sections we present the basics of GIS.