b) In the 1920s, Carl Sauer became influential in urban geography as he motivated geographers to study a city's population and economic aspects with regard to its physical location.
d) Throughout the 1950s and 1970s, geography itself became focused on spatial analysis, quantitative measurements and the use of the scientific method.
a) At the same time, urban geographers began quantitative information like census data to compare different urban areas.
e) Using this data allowed them to do comparative studies of different cities and develop computer-based analysis out of those studies.
c) By the 1970s, urban studies were the leading form of geographic research.
