First edition of d’Angeville’s revolutionary publication, the first major work arranged around thematic maps.

D’Angeville (1796-1856) can be credited with refining and expanding the application of the “chloropleth” map first developed by his predecessors Baron Charles Dupin (1784-1873) and Andre-Michel Guerry (1802-1866). These are maps in which areas are shaded or patterned in proportion to the measurement of the statistical variable being displayed on the map. While Dupin had focused on education and Guerry on crime and other “moral” phenomena, D’Angeville expanded his study to include not only these but variables related to economics and public health. The 16 maps included in his Essai sur la statistique address such wildly diverse variables as population density, rate of population growth, number of farmers, development of industry, army rejections for insufficient height or poor health, education level, illegitimate births, foundlings, number of civil suits, incidence of tax evasion, and even numbers of doors and windows in dwellings.

Though each map addresses only a single variable, by clever pairing of maps on facing pages D’Angeville invites hypotheses about how two or more variables might be causally related. For example, the patterns of distribution on map 9 (rates of primary education) and map 10 (doors and windows per 100 inhabitants) are strikingly similar.

D’Angeville (1796-1856) produced maps of much greater sophistication than his predecssors, and his Essai has been described as “the first sweeping application of thematic cartography to national industrial and population data” (John Delaney, “First X, Then Y, Now Z: Landmark Thematic Maps,” at www.princeton.edu). Along with his predecessors Dupin and Guerry, D’Angeville’s central contribution was to show that social and “moral” phenomena could be analyzed and understood through statistical observation, a process made easier by the innovative graphical presentation of data.

References
OCLC #1306453. For a detailed study, see J. Konvits, Cartography in France, 1660-1848: Science, Engineering and Statecraft, pp. 149 ff.