Figure 4From: Building blocks for automated elucidation of metabolites: Machine learning methods for NMR predictionPCA analysis of the numerical attributes in the descriptor set. The symbols correspond to the four different proton categories suggested in [9]. "○" for protons in aromatic rings, "△" for protons in non-aromatic π systems, "+" for protons in rigid aliphatic systems and "×" for protons in non-rigid aliphatic systems.Back to article page