Geography Reference
In-Depth Information
Fig. 2 A spatialised ringmap of 'main job' (colour), with an inset layering this on 'job travel'
(scaled to extrusion). Each ring represents a CT of Halifax, Canada in the 1970s and each sector
displays a 5-min interval of a 24-h day. Rings are arranged from the inside outwards in order of
proximity to the city centre to assist in relating urban structure to activity patterns (Zhao et al.
2008
, p 203)
city centre, so the spatial dimension is effectively abstracted down to relative
centrality. Against this a single selected activity can be viewed with a very explicit
and detailed focus. To do this and to stress temporal patterns, time is accentuated
through the detail of its reporting and by its illustration in a circular, cyclic pattern.
Combined with the coding of space into a centrality measure, the rhythms of work
and travel, the linkage between them and offsets with location of different suburbs,
can be detected quickly and easily. The patterns show that the 'main job' activity
(depicted by colours) was spatially concentrated in CTs that were close to the CBD
and temporally concentrated between 8 am and 5 pm with an hour long low (i.e.,
lunch break) in the middle. Meanwhile the 'job travel' activity (depicted by extru-
sion) peaked around the start and end times of the 'main job' activity, exhibiting a
small peak around lunch time that was more evident for the CTs that were not far from
the CBD. The patterns suggest that the two activities were closely related, as one
might expect. Such clarity may not emerge for a larger city, but the concept of relative
accessibility to multiple centres of core functionality can possibly be explored to
unpack movement in a polycentric metropolis.
These two examples are given to provide an insight into visualisation perfor-
mance for a urban movement pattern of commuting that is fairly familiar to a
general audience. Two things are clearly missing. The first is a mention of time-
lines (Hägerstrand
1970
), the ubiquitous but ephemeral product of all animals and
