In the forthcoming English translation of Security, Territory, and Population, Foucault discusses the notion of the “specific qualities” of a territory (as Elden points out, in a phrase omitted from the original 1991 publication, “within its frontiers.”
Foucault observes in STP that this makes the modern era the era of statistics:
Because statistics is etymologically knowledge (connaissance) of the state,* the knowledge of forces and resources which characterise a state at a given moment. For example, knowledge of the population, measured in its quantity, measured in its mortality, its birth rate, estimation of the different categories of individuals in the state and their wealth, estimates of the potential (? virtuelles) disposable wealth in the state: mines, forests, etc., estimates of the value of products, estimates of circulating capital, estimates of the balance of payments, measures of the effects of taxes and imports…all essential for the knowledge of the sovereign (trans from French edn. p. 280)
*Here Foucault footnotes the origin of the term in German as Statistik to Achenwall in 1749. Writing 2 years later in The Taming of Chance, Ian Hacking gives the same etymology.
The things listed by Foucault are all geographical, and during the nineteenth century many attempts were made to map them, especially by Charles Joseph Minard.
Today Minard is well known for his Napoleon map because it is heavily promoted by Edward Tufte:
But Minard drew many other maps and was primarily concerned with Foucault’s list (wine exports, circulation of people via railroad etc.).
Circulation of goods (1844)
Circulation of passengers (1845, his first map, the width of lines is proportional to number of travelers, a favorite Minard design element).
The first choropleth (shaded area) map was also invented at this time (1826) by another Frenchman, the Baron Charles Dupin.
Both of these men, and others such as D’Angeville, Quetelet, etc. were trying to “think out space” as Foucault says elsewhere.