00393nam a2200133 a 450000500170000002000140001708200170003110000220004824500510007026000420012130000240016349000470018770000250023420251203110225.0  a019233655  a910.285bBUR  aBurrough, Peter A  aPrinciples of geographical information systems  aOxfordbOxford University Pressc1998  axiii,306p.c25cm PB  aSpatial information systems and geostatics  aMcDonnell, Rachael A