Yukio Sadahiro Analysis of surface changes using primitive events. 523-538 2001 15 International Journal of Geographical Information Science 6 http://taylorandfrancis.metapress.com/openurl.asp?genre=article&issn=1365-8816&volume=15&issue=6&spage=523 db/journals/gis/gis15.html#Sadahiro01