161 "The weakness of current cartography is its poor representation of time. The surface of the earth is treated as a static thing." (Anselm Hook) As the world accelerates towards an uncertain future, and gathers more and more data in its past, the tools for visualising space AND time are in short supply. There are numerous experiments, but little solid support in tools or data structures for representing the 4th dimension (when we're still getting used to the 3rd dimension in GIS). We should be able to rewind continental drift to Pangea, track shifting political boundaries, monitor rapid environmental change and urban sprawl. I will survey the current state of support for Time in Geo (from WMS Time Series Support in Mapbuilder, to GeoRSS time navigation in worldKit, to BBC Interactive Time Maps, and hacks morphing the London Tube Map to journey duration, to .. research in progress), sketch out the possibilities, and put forward that the built-in temporal aspects of GeoRSS may be the key to wider application of Time to GIS. FOSS4G2006 - Free And Open Source Software for Geoinformatics Session 10 : SDI-OGC Mikel Maron mikel_maron@yahoo.com Mikel Maron mikel_maron@yahoo.com <MaKaC.conference.ContributionType object at 0xb420ccec>