Spatial Boundaries / Thresholds / Gradients

In North by Northwest, Cary Grant is attacked by a crop dusting airplane in an open field.  He manages to escape by stepping in front of a speeding truck, causing the plane to crash.   Considering the dramatic tension that emerges from machines and humans in proximity, we are inured to the bus passing us on the sidewalk, to the trucks passing the bicycle lane, to the cars adjacent to playgrounds.  Perhaps that’s because the landscape of the city is encoded with a social contract in the form of painted lines, material changes, curbs, fences, walls, buildings, and other regulating boundaries.   This materialization of bondaries allows us to cohabitate in a landscape with amazing density.

Instructions

Visit an existing park, or trace over an aerial or plan, exhuasting every boundary or threshold - whether expressed as a physical assembly, or implied - whether constructed by human beings, naturally formed, or accidental.

Develop a rigorous system of notation (e.g. linetype and lineweight) to visually classify different qualities of boundary: graphical systems (cross walk, parking lots), changes in material (blacktop to grass to wood) , shifts in surface elevation (height change, curbs), vertical surfaces (fences, storefront windows, walls), overhead (roof edges, tree canopies, or transition to different environments (the edge of pond, or a beach, etc.) 

Possible Tools:

Black technical pens on paper, Adobe Illustrator, Adobe Photoshop, Nodebox

Relevant Texts:

Catalin Avramescu, A Country in Lines.
Allen Stan, From Object to Field. 
Allen Stan, Mapping the Unmappable: On Notation (link)

Other Inspiration:

SURFACE, a film from underneath (video)
Albert Pope, Ladders.

ChicagoParks to Reference:

Use any park as a constraint or reference, exhausting each environment.  (link)