Urban economics is generally the economic study of towns; as such, it involves using the tools of economics to evaluate urban issues like crime, education, open transit, housing, and local government finance. More narrowly, it is any branch of microeconomics of which studies urban spatial structure plus the location of families and firms. Urban economics is rooted in the location theories of von Thünen, Alonso, Christaller and Lösch that began the process of spatial economic analysis.