In this video is described how to modify comples symbols in a vectorial layer with QGIS (http://qgis.org). The original file used in here can be found at github https://raw.githubusercontent.com/dieza/curso_r/master/taula_incompleta.csv. The whole set is about the circulation of obsidian in the western mediterranean during the Neolithic. Terradas, X., Gratuze, B., Bosch, J., Enrich, R., Esteve, X., Oms, F. X., & Ribé, G. (2014). Neolithic diffusion of obsidian in the western Mediterranean: new data from Iberia. Journal of archaeological Science, 41, 69-78. Tykot, R. H. (2017). Obsidian Studies in the Prehistoric Central Mediterranean: After 50 Years, What Have We Learned and What Still Needs to Be Done?. Open Archaeology, 3(1), 264-278.

This video is part of serie of them, the material needed to do the tutorial is indicated in the video itself or can be downloaded for github https://github.com/dieza/curso_r