**Des Cartes
Generates Aux Cartes Spectates
**

From Palsky (1996): Des Chiffres et
des Cartes, p.51-52

(translated by Daniel J. Denis)

*April 7, 2002*

CHARLES DE FOURCROY

Much progress in the field should
be attributed to works published at the end of the 18th century and beginning
of the 19th century. Among these, one of the most remarkable is *Essai** d'une table poléométrique *by Charles de Fourcroy,
dated 1782. De Fourcroy is without a doubt, one of
the first to employ proportional geometric figures to translate and compare
quantities representing the occurrence of urban surfaces: "If we have the
surfaces (i.e., areas) of all the cities/villages in the table, or the
proportions representing these cities, transformed into cross-sections, each of
equal extension, and each on the same scale; then if we successively put one on
the other, from the largest to the smallest, and joined all by one of their
angles; these squares would overlap relative to their size, and the whole would
form a kind of table that visually represents an idea of the actual proportion
that can be found between the surfaces of these different cities. We could as
well find in this table two cities of equal size, cut their squares diagonally,
and have the table represent only half of each; which essentially means the
same. Such is the attached figure, which requires no further
explanation" (figure 15).

The *Table poléométrique
*highlights more specifically, by the strict use of the variation in size,
the cartographic works of engineers of bridges and roads from 1840 to 1870.
Graphic innovation goes hand in hand with demographic preoccupations, with a
concern for the urban settlements: "Many new cities formed in France under
the reign of Louis XV [...]. I don't know if in these circumstances we know
exactly why these cities grew so much in size, but perhaps it is due to two new
war cities [...] with the necessary
size-increase of many other cities. An opinion of this kind seemed to me to
require some data or evidence". Or again: "There must exist
between the surface of a city and the number of inhabitants a certain
proportion more advantageous than all other, where it constitutes the most suitable population, a question
I have not addressed, though it is not of immediate curiosity." It is thus
as much by the graphic, as it is with
thought, the action of "voluntary geography", that Fourcroy precedes the creators of modem cartography,
a cartography adapted to the quantitative information in the following century.

The *Table *established by Fourcroy
signals a fundamental moment in the evolution of the graphical method. We see
the passage to the abstract, to fictitious features. By these proportional
triangles, the author constructs an image that does not return/relate to its
original existence. As J. Bertin notes, "you would
have had to be in the 14th century to foresee at Oxford, and the 18th century
to discover with Charles de Fourcroy, that the two
dimensions of the sheet of paper could represent something other than just
visible space. It was, in reality, going from a simple representation to a
"system of signs" which was complete, independent, and possessed its
own laws and properties, this is to say, its own
"semiologie." Charles de Fourcroy's table contributes in freeing the graphic from
the usual interpretation of the world. The center of interest is close to that
of Noel-Laurent Duchemin, but the world of expression
is fundamentally novel. In addition, the
graph is an applied graph. It facilitates the bringing together of, and
comparing of new information.

We
can mention that in this first example, a geometric surface does not translate
to an extent the urban surfaces, even if the demographic concerns/details are
subjacent. There remains to show that the style can express all numerical data.
It is difficult to measure the real influence of the poleometric
table, but another work confirms for us, through diagrams, graphical
translation of statistics.

4/8/02 11:05 AM