00298nam a2200109Ia 450000500170000000800410001708200120005810000170007024500510008726000420013830000080018020260224040927.0260224s9999||||xx |||||||||||||| ||und||  a910 CHA  aChang, K.T.  0aIntroduction to geographic information systems  aBoston : Mc-Graw Hill Book Co. c2002  a348