new Villa-Lobos Website in Indiana):
This technique, invented by Joseph Schillinger (1895-1943), and first used by him in the late 1920s, takes pictures of real-world things - skylines or mountains, for example - and turns them into musical phrases. It's analogous to digitization, I guess, if I'm not mixing digits, analogues and/or metaphors. Prof. Tarasti explains:
"...one needs a photograph of a mountain, landscape or a hill, whose contours are transferred onto graph paper. One then writes vertically in the margin, working upward through 85 tones in chromatic order (i.e., of the tempered scale) from C to C." - Tarasti (1995), p. 376
Apparently George Gershwin used Schillinger's system when he was writing Porgy & Bess. Villa-Lobos used the system in New York Skyline Melody (1939), before he moved to a bigger canvas, both in his input (the mountains around Rio de Janeiro), and output (a full-scale symphony). He also used it in on a picture of Nicholas Slonimsky's family - a story told in Slonimsky's 1945 book Music of Latin America.
The picture above is taken from Carlos Kater's article "Villa-Lobos e a 'Melodia das montanhas': Contribuição à revisão crítica da pedagogia musical brasileira", Latin American Music Review / Revista de Música Latinoamericana, Vol. 5, No. 1 (Spring - Summer, 1984), pp. 102-105. I discussed NY Skyline in this post at The Villa-Lobos Magazine.