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I’ve been reading through a recent book entitled “Qualitative GIS: A Mixed Methods Approach” by Meghan Cope and Sarah Elwood, hopefully I’ll post a full review it soon. In the meantime however, I want to think about one of the sections in it by Marianna Pavlovskaya, specifically her discussion of whether or not GIS is inherently a quantitative tool. I tend to agree with Marianna on one front – rarely do most GIS users directly engage with the quantitative aspects of GIS, use of GIS becomes about spatial reasoning with overlays and logical tesselations of geometry and the impact of visual depiction. On the other hand though I offer a photo of books currently on my desk:

Figure 1: Some books on my shelf

I think there is a serious point here; GIS is a tool- people are happy to use tools to get the jobs they need doing done, I trust an allen key to undo parts of my bicycle without breaking them, and tighten them to a safe level. I don’t however need to know exactly how the tool is made, I just trust I know how to use it. The same is true of GIS, functions such as overlays are tools (in fact this is the exact terminology that ESRI use in ArcGIS), you use tools to analyse maps in a non quantitative way, because you reason and understand their usage; I don’t specifically need to know how the overlay works in a mechanical sense, just that it does. It is generally that case that such tools, even simple tools have a basis in quantitative fields, often mathematics; an overlay is a topological operator deriving from that branch of mathematics.

Now, in a GIS such tools are formed from solving challenges in ‘computational geometry’, and I agree with Pavlovskaya again in that ‘computerisation is not quantification’, except that in this case; that is exactly what it is. There are numerous instances in GIS, shown through point pattern analyses, topological functions and distance decay in which it is clear that GIS is a quantitative tool with a quantitative development.

So is Pavlovskaya wrong then? Well, no. There are different kinds of users in GIS and for the most part users aren’t looking ‘under the bonnet’, to them a GIS is a set of tools, the use of which causes them to construct (make) GIS as a non-quantitative thing. What seems strange is that in looking for opening for non-quantitative GIS in this perspective, the current way of constructing GIS quantitatively had to be challenged, or seen to be wrong and somehow misguided. In my eyes the interesting thing that comes out of this discussion is the idea of abstraction.

In a sense quantitative, or technical, ways of seeing are increasingly being abstracted: bundled and enclosed into something you can think of as a ‘black box’. This encourages engagement as the most common user experience is a qualitative one, as qualitiative experiences for most are more intuitive – generally we have the appropriate skills to deal with such experiences, but may need to learn the skills to engage quantitatively in a complex system such as GIS. Software such as GIS packages have the effect of making previosuly difficult quantitative functions much more accessible, even a measure of straightline distance is a quantitiative function – the Pythagorean theorum, and this can be done in Google Earth and Google Maps which are probably the most accessed GIS in the world (if not also the most accessible). I think the question we have to ask is: what are the tradeoffs in making quantitative functions more accessible, in having them reconstructed as qualitative tools? The obvious answer to this is that when things are conceived as ‘black boxes’ they are exactly that: we have no idea of what is going on inside them. Thus, qualitatively, we have to decide whether or not that is important; in fact for qualitative GIS is may not be that important, as the world is reseen with ‘fuzzy’ characteristics.

References

Cope, M. and Elwood, S. (2009) Qualitative GIS: A Mixed Methods Approach. Sage, London

(much of Pavlovskaya’s chapter also appears in the following paper)

Pavlovskaya, M. (2006) ‘Theorizing with GIS: A Tool for Critical Geographies?’ Environment and Planning A 38(11) 2003-20

Addendum

Muki Haklay often blogs about usability and critical GIS, amongst numerous other things of interest at his blog here.