If asked “What should it mean,” I might be more inclined to pontificate.  In response to “What does it mean,” however, I can only speak for myself.  My interaction with Ian McHarg involved years as his GIS guy.  Thus, my own perspective on designing with nature relates more to medium than message.

Ian once pulled me aside with characteristic urgency to assert/request that “We should be able to use GIS like watercolors.”  Though my mind immediately focused on how, it occurs to me in retrospect that the more interesting question is why.  As a watercolorist himself, McHarg was well aware of what that medium had to offer.  In the hands of one whose role was not merely to document or express but also to envision and create, watercolor made it possible to engage human faculties not entirely subject to cerebral control.  It is the nature of that medium. 

Though GIS has yet to achieve its potential as a medium for design, that potential remains apparent.  To better realize it requires only that we embrace the nature of this medium.  No, it’s not the same as watercolor, and we shouldn’t pretend that it is.  Instead, we should recognize that this is a medium with unprecedented power to enable large and varied groups of constituents to access vast amounts of geospatial data and to interpret those data in ways that can be brought to bear on a real world in real time with real consequences. (OK, a little pontification after all.)