A color coded map of the spread of Phylloxera in the Gironde from 1868 to 1877
The previously published map of the progress of Phylloxera in Northern Portugal during 1880 uses solid color to indicate the intensity of the devastation from Phylloxera at a given time. The map featured in this post illustrates the spread of Phylloxera in the Gironde over time using color coded stars. At first glance, I even thought the stars were those tiny foil stickers so often used in elementary school. This map reflects a more complicated objective and I honestly have a difficult time understanding the chronology without constantly referring to the legend.Here is a close up of the legend. I do not yet understand how the color scheme was devised. And here is a close up of the map.
 Trimoulet, A. H. Carte de la marche de la Maladie dite du phylloxera dans le département de la Gironde. 1878. Gallica Bibliotheque Numerique. URL: http://catalogue.bnf.fr/ark:/12148/cb40742516r