Exercício 3: Monitorização e detecção multitemporal de alterações - Continuação   Classification result showing lava (white) and non-lava (black) for the Landsat images of 11 December 2001 (left) and 15 January 2003 (right). Aritmética de bandas     Classification result showing lava (white) and non-lava (black) for the Landsat images of 11 December 2001 (left) and 15 January 2003 (right), filtered with a 5x5 median filter.