Computers, Society, and Nature

In their post on temporality in GIS, Outdoor Addict brings up the date of the Langran and Chrisman paper–1988.  That was a long TIME ago!  So this brought to mind for me, the same as it appears to have for many others, that there must be many innovations since 1988 allowing us to better represent time in GIS datasets.  The sliders on internet graphics, or like in agent-based modelling, where the slider moves, changing the time step and the data displayed; the same thing in Google Earth, you can witness both historical changes and the visualization as day turns to night–all are examples of how temporality is displayed today: digitally.

But these are ways of displaying data, and as someone noted, not necessarily the best way of analyzing data.  This made me think further, though.  At each time step, the “event” is static in that time.  The process is fluid across time, but the events are solidly placed within time.  So my question is: why must we do time differently?  Couldn’t we have one map, where red dots are 1998, blue dots are 2000, and yellow dots 2012?  We could see where time factors in, and the data could be in one attribute table.

I am analyzing landscapes for another project, and we are comparing 1998 to 2004.  We have two maps with essentially the same parcels, and are trying to compare the land use.  We have one attribute table with all the parcels, and then have the time steps as individual fields, listing the land use at that time.  It can be displayed at whatever time step we like.  I can see where the authors suggest this is loading a lot of additional data, however.  If you have upwards of 20 000 unique attributes, say, but 75% of them weren’t changing, you would still have to store each time step of land use where nothing was changing.  But as the authors note, it seems the space-time composite is the best way to go forward, as combining all the temporal events in one space/data set minimizes the chances for error.

So at this point I’m not sure… where do we go from here?

–sah

Tags: Temporal GIS

This entry was posted on Thursday, March 22nd, 2012 at 11:55 pm and is filed under 506, geographic information systems. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.