Principles of geographic information systems ITC core module par By, Rolf A., Sc, M.C. Ellis B., Kainz, D.W, Knippers, R.A, Kraak, M.J, Krol, B.G.C.M, Radwan, M.M, Sides, E.J, Sun, Y., Weir, M.J.C, Van Westen, C.J