When the focus of interest in geographical systems is at the very fine scale, at the level of
streets and buildings for example, movement becomes central to simulations of how spatial
activities are used and develop. Recent advances in computing power and the acquisition of
fine scale digital data now mean that we are able to attempt to understand and predict such
phenomena with the focus in spatial modelling changing to dynamic simulations of the
individual and collective behaviour of individual decision-making at such scales. In this
Chapter, we develop ideas about how such phenomena can be modelled showing first how
randomness and geometry are all important to local movement and how ordered spatial
structures emerge from such actions. We focus on developing these ideas for pedestrians
showing how random walks constrained by geometry but aided by what agents can see,
determine how individuals respond to locational patterns. We illustrate these ideas with three
types of example: first for local scale street scenes where congestion and flocking is all
important, second for coarser scale shopping centres such as malls where economic
preference interferes much more with local geometry, and finally for semi-organised street
festivals where management and control by police and related authorities is integral to the
way crowds move
