"Distribution of the varying intensity of skin colour" (Distribuzione della Varia Intensità del Colore della Pelle), data for native populations published by R. Biasutti in 1940 that is Brace's map on human skin color in 1473 (the 15th century).
Jablonski NG, Chaplin G. 2000. The evolution of skin coloration. J. Hum. Evol. 39:57–106 
History on Wikimedia: Based on File:Map of skin color distribution.gif (uploaded as fair use image 2 November 2004, deleted 6 November 2005), a scan of a reproduction by by Dennis O'Neil  of the map   "Distribuzione della Varia Intensità del Colore della Pelle" in Renato Biasutti, Le Razze e i Popoli della Terra: Volume Primo--Razze, Popoli e Culture (1959).
Recolored it in accordance with File:Felix von Luschan Skin Color chart.svg.
Reflectance spectrophotometry is a much more modern way of measurement of human skin color. See Jablonski's work.
The best known of these maps is that composed by Renato Biasutti, which was based on von Luschan's chromatic scale. This map has gained broad circulation in several widely distributed publications (Barsh 2003, Lewontin 1995, Roberts 1977, Walter 1971). According to Jablonski (2004), some areas where data could not be obtained were filled in based on data from other areas.[1]. A map supplemented by Jablonski: [2]
Original sources for the original maps were:

Barsh GS (2003) What Controls Variation in Human Skin Color? PLoS Biol 1(1): e27. doi:10.1371/journal.pbio.0000027.
Modern Human Variation: Overview (1998-2009 by Dennis O'Neil).The Ogre  00:05, 7 December 2009 (UTC)
Jablonski NG, Chaplin G. 2000. The evolution of skin coloration. J. Hum. Evol. 39:57–106also reprinted in:

Barsh GS (2003) What Controls Variation in Human Skin Color? PLoS Biol 1(1): e27. doi:10.1371/journal.pbio.0000027
Jurmain, R., L. Kilgore, W. Trevathan, (2009). Essentials Of Physical Anthropology. Belmont (CA): Wadsworth Publishing. ISBN 0495509396. This work notes: this maps quality is very low but is all that is currently available.
Original:  The Ogre Vector:  Crisco 1492