GIS & Housing

The book is intended to introduce contemporary housing issues to a non-specialist audience and to encourage housing policy professionals and housing experts to use GIS concepts, methods, and techniques to investigate housing-related policy and implementation questions. As authors, we are clear that the context and the application domain (housing) and the questions posed to understand, explain, and shape housing policy must determine the use of the methods - in this case, the use of GIS mapping and spatial analysis. Therefore, we begin by framing the first chapter in contextualizing housing in the United States. In Chapter One, we propose that housing, understood to be a basic human need in all societies, is much more than the provision of shelter from the elements. Housing is a cultural phenomenon, in that housing morphologies and settlement patterns are as likely to reflect a society’s dominant cultural ethos which may be as significant or more significant than building with considerations about suitability of materials, methods of construction, or costs.  American urbanization and housing settlement patterns were influenced by the City Beautiful movement and societal considerations that sought to reduce density and overcrowding in urban areas. The chapter proposes that the application of a geographical lens can create a robust understanding of housing related issues at the neighborhood/human scale and advocates for the use of Geographic Information Science concepts, methods, and techniques to formalize geographical analyses of housing questions. Maps and data are used to explain housing geographies and highlight how the use of geographically referenced, publicly available information can be used to support policymaking. 

Chapter Two addresses the demographic shifts in the United States since the early 20th century to establish that demographic realities, regardless of their cause, influence housing production. At the same time, housing production innovations were made possible because of technological advances. Just as in the late 19th century, indoor plumbing and sanitary sewer systems allowed changes in the layout of individual houses and apartment buildings, the invention of indoor air conditioning systems allowed large-scale settlements to develop in previously inhospitable climatic zones. Likewise, advances in refrigerated trucking, and the development and growth of an automobile-oriented culture influenced American urbanization since the 1920s, trends that accelerated after 1945 as a result of the post war baby boom. Suburbia was “invented” to advance an ideal of a nuclear family (with a working father and a stay-at-home mom), who lived in “safe” suburban residential environments spatially separated from unhealthy and unsafe urban workplace environments. This cultural ideal has prevailed for over 60 years and shows no signs of abating. Land use policies and practices supported and advanced these cultural ideals. Zoning imposed a pseudo-order on the landscape and was established using racist and exclusionary practices that created segregated neighborhoods. The chapter also discusses the rise and decline in investments to create public housing and ends with a brief discussion of gentrification.

Chapter Three expands the readers’ understanding about housing typologies. Non-specialists hearing the word “housing” typically use their own personal understandings of housing establishing a rudimentary binary classification that distinguishes between owner-occupied housing and renter-occupied housing. While this is an important distinction, there are additional architectural distinctions that become significant in the production and management of housing. The range of housing typologies discussed in this chapter creates distinctions by function: i) single family housing, ii) multi-family housing, and iii) institutional living quarters. From a planning and design perspective, each of these types of housing typologies can be further broken down based on sub-categories such as i) architectural styles (e.g., a single-family detached house), allowable height/volume (e.g., a non-elevator, walk-up building in a residential zone), number of individuals or households accommodated (e.g., group quarters such as college dorms), and ownership (e.g., condominiums). The chapter also discusses newer physical planning innovations in the housing sector such as the use of manufactured homes to address the housing shortage among low-wage workers, the legal and illegal conversions of homes to add space for expanding families such as a mother-in-law unit, or a rental unit to generate income for the house owner. The chapter also discusses policy innovations such as the Rental Assistance Demonstration (RAD) program developed by the US Department of Housing and Urban Development (HUD) that attempts to preserve affordable housing. The chapter concludes with a discussion about geographical data and the use of geospatial indicators that can be used to understand the land use planning implications associated with housing. Housing specialists eager to learn about the use of GIS to support their work should begin with a careful reading of Section 3.5.

Chapter Four shifts the focus from housing issues to a consideration of GIS. Geographic Information Science concepts require a preliminary understanding of data sources, databases, database organization principles, and data quality. The chapter begins with a discussion of different types of data sources. The primary data source for housing research comes from the US Census. Additionally, historical census data has been compiled and organized in formats suitable for research and analysis through the National Historical GIS. In order to take advantage of GIS, data needs to be locationally referenced, creating a unique spatial identifier - such as a street address to which other information can be linked. Chapter Four also discusses how to create and use derived housing variables (that are computed or estimated), and the challenges of working in data poor environments. A discussion of data quality includes the Modifiable Areal Unit Problem (MAUP), which is the cause of ecological fallacies in analyzing and reporting GIS data. The chapter concludes with a reminder to readers to be creative in identifying non-conventional data sources and engaging citizens in conducting housing research to solve the problem of “lack of data” at the neighborhood level. The chapter does not claim to be an introduction to GIS (whole textbooks have been written about how to use GIS) but it gets housing specialists prepared to have conversations and collaborations with GIS professionals.  

Chapter Five builds on the previous chapter and prepares housing researchers to understand the principles of spatial coordinate systems that allow geo-referenced data points to be displayed correctly on a map. It also explains the geo-relational principle wherein a unique location reference in one database or data table is linked to the same unique reference in another dataset. Using a locational reference to link different sets of data lies at the basis of GIS. Data about a location (in GIS terms, called attributes) gathered from different sources can be linked and analyzed.  For planners and housing researchers, this means that population data about a neighborhood (ZIP code) can be linked to housing prices in the same area and can also be linked to education characteristics at the same location. The chapter continues with a discussion of basic GIS operations that are used in GIS-based analyses and touches upon advanced methods such as spatial regression. 

Chapter Six is the most technical chapter in this book. GIS novices are urged to use a companion GIS textbook such as Albrecht (2007) and a planning methods book e.g., Ramasubramanian & Albrecht (2018) to extract value from this chapter. Chapter Six moves from the realm of using GIS to understand housing issues to considering the complex policy questions that preoccupy housing specialists and urban planners. Progressive housing activists and policymakers are consumed by addressing the housing supply crisis discussed in Chapter One by increasing residential densities. The authors discuss how GIS can support framing these policy conversations. Each section tackles complex challenges where multiple layers of data and evidence are linked to produce a coherent narrative to advocate for a particular set of policies. In this chapter, GIS maps are recognized as services that create just-in-time analyses for end users. GIS is also more robustly integrated with 3-D modeling and visualization, requiring advanced technical skills. The latest investments in GIS for housing use digital twins - where digital models of the urban environment are created in great detail to allow the testing of different scenarios or options. These technological advances push the boundaries of what is possible using GIS, and support future-oriented planning and decision making.

Throughout this book, we have discussed the power and potential of using a geographical lens to examine housing issues at different spatial scales. In Chapter Seven that concludes this book, we remind readers that GI technologies and applications facilitate academic inquiry but more importantly allow for a range of stakeholders to examine housing questions in relation to other city development challenges such as addressing infrastructure or transportation needs. Since housing is central to the lives of everyday people and housing challenges are experienced at the neighborhood scale, we have argued about the value and need for housing analyses to be conducted and communicated at the neighborhood/sub-city scale. We encourage educators in the design and planning professions to integrate policy and planning conversations - to further encourage professionals working in the built environment sector to work collaboratively to address housing production/supply challenges. We encourage bold thinking and forward-looking solutions to address the enduring housing crises in America to create sustainable and humane living alternatives for future generations.