Guelph: An Almost Typical North American Suburban Locale
In order to effectively test the TensorView tool, we have elected to conduct an example survey - searching for abandoned buildings in an urban area. For this, we have chosen the City of Guelph, a small suburban city of approximately 130,000 people located roughly 100km west of Toronto, as a study area (StatsCan, 2016). Though it was founded in the mid-1800s, a large part of its urban area has only come into existence since the Second World War and displays the characteristic low-density "suburban sprawl" land use of a North American suburb (Nechyba & Walsh, 2004). It is also somewhat unique, however, in that it is not considered to be part of the metro of any larger city - it is geographically isolated from both the Greater Toronto Area (GTA) and the Kitchener-Waterloo-Cambridge Tri-City, the largest nearby urban agglomerations. Due to this isolation, it is essentially a typical North American metro area in microcosm - large enough to have many of the features of larger cities, but small enough to make demonstrating TensorView feasible. The fact that Guelph, despite its comparatively small size, still contains some 800km of roads and tens of thousands of buildings indicates the need for such a tool in large-scale surveying for difficult-to-find features.
Figure 1: Approximate distributions of different urban forms in Guelph. The inset map shows its relationships with other nearby urban agglomerations (OpenStreetMap Foundation, 2017; European Space Agency, 2016).
Guelph consists of a small historical (late 1800s) downtown core, surrounded by prewar "streetcar suburb"-style development (Wheeler, 2003). The outer portions of the city consist of large single-purpose tract developments, divided between single-detached residential areas and heavy industry interspersed with low-rise commercial plazas of the "strip mall" variety. A general overview of the locations of these different development types in Guelph can be seen in Figure 1. Because of the city's extremely rapid growth into the surrounding countryside over the past 20 years, the newer developments also contain isolated "holdouts" - farms and historic rural properties that have become enveloped by suburban neighbourhoods and industrial parks.
The creation of an abandoned-building inventory also has some topical interest to the City of Guelph. Between October 2016 and March 2017, more than a dozen abandoned buildings, many of historical and heritage value, were damaged or destroyed in apparent acts of arson (Seto, 2017; Flanagan, 2017). Though the locations of some of these structures were known to authorities, all of the sites were sparsely monitored and lightly secured. A map of the arson locations relative to Guelph can be seen in Figure 2.
Figure 2: Locations of abandoned-building fires near Guelph (Seto, 2017; Flanagan, 2017; Robinson, 2017; European Space Agency, 2016).
The survey area itself consists of 14 different sub-areas covering a variety of urban forms in and around Guelph. These sub-areas include, but are not limited to, strip malls, streetcar suburbs, and rural backcountry, and were chosen to provide a general selection of Guelph's different features without requiring too much processing time. Taken together, these areas encompass some 17.3km of roads of varying types, from arterials to suburban side streets. An overview of the survey sub-areas in relation to Guelph and its various urban forms, as well as Guelph's relationships with nearby cities, can be seen in Figure 1.