Brasilia, Brazil, 29 March - 3 April 1999
The City Shaped: (ir)Regularity in experiencing
urban space
Assimina-Mina Courti
The Bartlett School of Graduate Studies
(Torrington Place Site)
University College London
Gower Street
London WC1E 6BT
England
tel (44) (0)171 637 8039
fax (44) (0)171 916 1887
email a.courti@ucl.ac.uk
The shape of urban space, outlined by the notion of the grid, is only
obvious when seen in a map or an aerial photograph; "from-without"
the geometry of the grid is exposed to vision at once, continuously. "From-within"
visibility is discontinuous, the geometry of the grid is
revealed and grasped sequentially by moving around in it.
This paper addresses the question of how the geometry of the grid becomes
intelligible while moving within urban space. Shape intelligibility, defined
as the correlation between the actual shape of space "from-without"
and the inferential shape of space "from-within", is explored
in the context of irregular and regular grids; the former represented
by the grid of the City of London , the latter by geometrically constructed
grid patterns with the same area contours. The aim is twofold : to see
how the shape of planned and organic urban grids can be reconstructed
as a mental picture, and also to complement syntactic analysis with tools
which provide data on the shape and the geometrical principles organising
the grid. The paper looks at the ways in which the spatial experiences
of a moving observer represented by the discrete shapes of spaces as seen
from different positions within the grid, are gradually orchestrated into
the spatial identity of the grid, defined as the mental (re)structuring
of its shape. This is achieved by means of the dialectics of visibility
: the interconnection between the view "from-within" and the
view "from-without".
The paper argues that the spatial identity of the city, is built from
the bottom-up by means of two operations : the detection of regularity
in the shapes of the visual fields available "from within",
and the detection of the potential spatial sequences allowed by the grid.
The former provides the best approximation to an overall view, by depicting
the elements of continuity "from- within" the grid, i.e. the
informationally stable with respect to the visibility they afford convex
areas. The latter describes the order of experiencing this regularity.
Spatial sequences, initially introduced as ordered series of the shapes
of the visual fields at successive positions within the grid, are superimposed
to the network of the informationally stable positions, in order to retrieve
spatial identity.
Analysis shows that planned grids, regardless of their degree of sophistication,
are easily grasped, generating trivial spatial identity, whereas the multiple
potential sequences generated by irregular grids provide a labyrinthine
spatial identity.
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