The start of all crime mapping starts with Adriano Balbi and André Michel Guerry who, in 1829, created maps that showed the relationship between violent/property crimes and educational levels. While this effort started in France, Joseph Fletcher concurrently created maps that showed the rate of male incarceration for serious property and violent crimes across counties in England and Wales, and in 1861, Henry Mayhew presented a number of maps displaying the English and Welsh county rates for a variety of crimes, such as rape, assault, bigamy, and abduction.
This started the trend of Cloropleth maps; documents which graphically displayed quantities of a construct within a certain region. Interestingly, the best example of these types of maps were started here in Chicago by Clifford Shaw & Henry McKay, whose maps represented aggregations of addresses of close to 3,000 male delinquents in Chicago for the period 1927 to 1933. According to The History of Crime Mapping and Its Use by American Police Departments (Susan Chamard, University of Alaska Press, 2006):
“The map featured polygon shading to indicate rates of delinquency. Like Breckenridge and Abbott, Shaw and McKay also constructed point maps of the locations of the homes of about 10,000 male delinquents who had come before the juvenile court of Cook County in the years 1934 to 1940. Shaw and McKay noted that the spatial distribution of juvenile delinquents’ homes remained fairly constant over these differing time spans, despite the fact that there was a high degree of residential mobility in various areas of Chicago. Their work, with that of others, gave rise to the social ecology approach to studying crime. This approach assumes that crime is to a large extent caused by community- and neighborhood-level variables, such as land use, infant mortality rates, mental disorders, tuberculosis, and the percentages of minorities and families on social assistance.”
Inspired by this work, most crime maps constructed before the age of computers was done at the University of Chicago Sociology Department. Among the earliest of these maps were done by social work educators Sophonsiba Breckenridge and Edith Abbott, who mapped where delinquent children had lived in Chicago over the period 1899 to 1903. According to Chamard: “This map, with each dot standing for one home, is an example of a point map—that is, a map in which points representing particular geographical locations, be they addresses or XY coordinates, are the main data element.”
The use of pin maps would transform the use of urban crime maps all over the world from an academic entity to an institutional device. In the late 1930s through the early 1970s, pin maps were used by the FBI, Chicago Police Department, and others to easily convey status and allocations of each department. The pin map is represented as literally a map with pins in the title picture of J. Edgar Hoover who would famously use this technique for organizing the FBI in Washington.