“…The Self-Organizing Maps (SOM) (Kohonen, 1990), an ANN with unsupervised learning is the other commonly used clustering algorithm in environmental data (Andina, Jevtic, Marcano, & Barrón-Adame, 2007). SOM is suitable for data classification because of its visualization property (Alvarez-Guerra, Gonzlez-Piuela, AndrTs, Gain, & Viguri, 2008;Seo & Obermayer, 2004;Vesanto & Alhoniemi, 2000). For example, the SOM has been used to identify patterns in satellite imagery in oceanography (Richardson, Risien, & Shillington, 2003); to visualize and cluster volcanic ash (Ersoy, Aydar, Gourgaud, Artuner, & Bayhan, 2007); or to estimate the risk of insect species invasion associated with geographic regions (Watts & Worner, 2009).…”