The View from the Road - the Potential of GPS Technologies to inform a Generative Approach to
Designing Visual Sequences for the Observer in Motion
Katharine S Willis, BA(Hons), DipArch, March
This paper proposes a new approach to understanding of how we can create legible cities, through a study on generative approaches to navigation, orientation and identity. A citizenís understanding of a city is formed in their cognitive memory by paths they take, features that they use to orientate themselves; a conscious sense of the displacements of the body, a mental mapping of the space. In a dynamic environment we are constantly engaged in the attempt to organise our surroundings, to structure and identify them.
Due to the complexity of the urban environment is experienced it has often proved difficult to find suitable technologies which enable human mapping and orientating techniques. GPS is an emergent technology that has the potential to allow us to identify new aspects of journeys and of our surroundings.
The paper will seek to propose the use of GPS to develop a generative approach to exploring navigable, rich urban environments. It will propose that motion through the urban fabric can be enhanced to enable the user to respond dynamically to the city environment where existing human navigation techniques often fail. It will initially seek to outline how an individual understands a city through mapping and orientation. It will then review some projects that successfully engage the motion of the citizen through a space, creating environments which aid way-finding strategies.
The paper will then move on to look into generative methods for developing spatial sequencing that are meaningful. By analysing the patterns, landmarks and paths that individualís store as memory of place, it will start to define some of these strategies. It will further discuss the validity of starting to map some of the results of these generative strategies back into concepts of urban form.
The ability of an individual to navigate in an environment can be broke down into two categories: procedural and route knowledge. Procedural knowledge is usually gained by personal exploration of a new area, and is ordered sequentially and often structured around features such as landmarks.
Meanwhile survey knowledge is attained through exploration of an environment using multiple routes, and results in an exocentric metal representation of an area as a birdís eye view; a cognitive map. Such navigational awareness is formed by sequential travel and involves going through a dynamic process of learning about the environment. The key features that enable people to develop and use cognitive maps of their environment are:
In the process of wayfinding the strategic link is the environmental image or cognitive map as it also referred to, as opposed to a conventional cartographic map. This is the generalized picture of the exterior physical world that is held by an individual . They are highly personalised, and different people develop varying levels of maps.
Paths, Nodes and Landmarks
Paths are channels along which the observer occasionally or potentially moves. They may be streets, footpaths, pavements, canals, rivers or railway tracks . For many people these are the predominant elements in their cognitive maps. People observe the city whilst moving through it, and long these paths and other environmental elements are arranged and related. When moving along a path an individual experiences an organised sequence in which phases follow each other meaningfully in an order. The critical aspect of this experience is that it is perceived whilst in motion. In fact observers are aware of, even in remembering the dynamic quality of a path, the sense of motion along it. Objects or landmarks along the path can define it more clearly, or heighten the effect of motion.
The experience of the environment along a path or route also has a sense of spatial sequence. The continuity and rhythm are similar to music or film. But the critical aspect is that vision is the principle sense. The attention of the observer is caught by both near and far objects, such as signs, traffic, the sky, topography and buildings.† These form landmarks along the route, by becoming part of the sequential experience of the observer. The observer locates these moving objects and space in a total structure, orientating themselves with regard to the world around them.
GPS stands for Global Positioning System, a series of twenty four satellites and receivers that are capable of listing precise locations. Signals from the satellites are broadcast at a known interval based on atomic clocks, which are picked up by GPS receivers. These devices trilaterate the radio wave data and calculates, to varying degrees of accuracy, the location on Earth. The accuracy of the positional information can vary from one kilometer down to millimeters. In order for GPS to function properly, a receiver must be in contact with at least four satellites to determine a 3D position using latitude, longitude and altitude.
NAVSTAR Constellation: 51 32 N 0 5 W
†____: Aug 02 11:9:27 2004 ††††††††††††††† 41°21'58.56"N 1°09'58.15"E
Figure 1: raw Satellite co-ordinate data
The GPS receiver employs an interface that provides an interpreted format of the satellite data, which is in essence displays a trace. The record of the satellite positional data appears at the bottom of each display: the identifying numbers of the NAVSTAR satellites, the time spent in contact with them and the number of data points collected by the receiver. The display is based upon a trace; a sequence of points that registers the movement of the receiver across some physical space.
However GPS receivers also enables the user to input information. A typical handheld GPS receiver device has features which include:
Figure 2: screenshots showing display features of Garmin handheld GPS device 
The potentialities for GPS lie in the fact that the location data requires that both movement (trace) and inertia (point) be registered so the map-user operates in an layered space. This transparent layering enables new interpretations and actions of the user, and consequently offers opportunities for re-visualising spatial cognition. The elements of architecture such as landmarks, routes, and environment are transformed and redefined in the interactions of this data. This scale-less information zone constitutes not simply the representation of a pre-existing space but another space altogether .
Surprisingly, the possibilities for disorientation are also created, not in the physical environment but instead in the technology that assures orientation and this throws open a further set of possibilities. In this situation GPS provides the chance to map some of these serendipitous actions; the discovery of landmarks and districts only on approach as if by chance .
Figure 3: screenshot of Fugawi 3D topographical GPS mapping software 
The GPS device can be used to map the motion through an environment, whether this motion be planned or serendipitous. By allowing people access to the mapping of their environment and where this technology becomes increasingly ubiquitous and quotodien the physical environment becomes transformed. The resulting GPS data can be used to enable generative strategies, thus improving the quality of the sequencing of the environment. It is layered with multiple readings, both planned and spontaneous, both informed and data poor.
Generative learning takes place when links are generated between the contents of short-term memory and our knowledge base, or long-term memory.  An individual's memory will further improve dramatically if some of the to-be-remembered information is self-initiated. This layered condition of data generated through the GPS and real world information enables generative learning through the active integration of new ideas with the learner's existing mental mapping devices. GPS data, by supporting, enhancing and interacting with the existing cognitive mapping strategy of the individual, enables them becomes immersed in a generative learning environment.
The multilayered environment, formed through the overlay of cognitive and GPS mapping strategies is rich, but there exist at the juncture some voids in the provision of data. These voids prohibit generative strategies since they create conflicting accounts of the urban environment which cannot be easily interpreted. These voids can be identified as:
However they also present opportunities for the design of spatial sequences for the observer in motion. Devices and structures can be created that inhabit these void spaces and enable meaningful generative learning of an environment. These interventions can either be personalised or generic, but will inevitably combine to create new topographies.
Cognitive mapping of the urban environment is the individualís ability to mentally map a space, whether it be familiar or unknown. This process, also known as wayfinding utilises a number of strategies, such as identifying routes, recognising landmarks, sequencing points or nodes and chunking of the environment into zones. One of the critical requirements of navigating the city is to undertake the task whilst moving through it, and to interpret this experience an organised sequence in which phases follow each other meaningfully in an order. This paper proposed that motion through the urban fabric can be enhanced to enable the user to respond dynamically to the city environment where existing human navigation techniques often fail.
As an emergent technology, GPS enables an individual to obtain accurate data as to their location, and to view their movement through the city as a trace display. It also provides the opportunity for the individual to personalise the interpretation of this trace, by creating input, which enhances the information. Through the availability of this information the physical environment becomes transformed; it becomes effectively overlaid with a data space. Through the process of feedback and exchanging of data and memories, a change of the existing notion of time and space which is based on the linear, static understanding of the world is initiated.
The resulting multi-layered mapping provides the opportunity to utilize generative learning approaches to enhance existing cognitive mapping devices. Generative learning takes place when links are generated between the contents of short-term memory and the individualís knowledge base. In identifying the junctures between the GPS and cognitive mapping strategies, numerous and rich opportunities for physical interventions in the urban form arise.
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