Posts Tagged ‘errror’

Visualizing Uncertainty for the Layman

Thursday, March 8th, 2012

I want to respond to the ideas put forth by “SAH” and extrapolated on by “Madskiier_JWong” in relation to visualizing error. I agree with “SAH” that most people don’t think about the error in their geospatial data (although they certainly acknowledge its existence), nor even ask about it either. I also think “Madskiier” is on point when he talks about built-in “structural guidelines” for programs to show people how to build in error in a visual manner. In fact, I think this point is definitely something the authors Gary J. Hunter and Michael F. Goodchild talk a bit about in relation to Y. Bedard’s 1987 work establishing how we might strengthen geodetic control networks and define and standardize technical procedures – all in an effort to cut down error. On the converse side, I agree with more with Giles M. Foody’s perspective on uncertainty for the layman. He does a good job of covering this topic too when he writes that “it is, therefore, most unfortunate that the ease of use of many GI systems enable users with little knowledge or appreciation of uncertainty to derive polished, but flawed, outputs” (116).

But I want to take this discussion a step further and, perhaps, out of the cyber-realm of the practitioner or researcher to think about what error, or uncertainty, might actually mean for the layman who uses the end product of these practices. Hunter and Goodchild talk a bit about this in their article under the heaidng of “Progress in Error Visualization.” Particularly, they talk about adding a layer to a map to convey uncertainty, having given cells display multiple types of classes, or even varying data displays to convey a level of uncertainty(55-56). Yet these practices seem far from common, at least to me, in most of the products that average people rely on during their daily lives. The authors note that their colleagues “would like to take this testing further and establish laboratories in which practitioners would be invited to use spatial databases for real-life problems while under observation” (57). Well, not to be rude, but it’s about time.

I realize I may harp on my GPS a bit too much as part of our class (hey, it’s my only form of LBS), but what happens when the data programmed into it contains errors such as changed street names, landmarks or objects at different grid points, or restaurants that no longer exist? I’ll tell you what happens – I get lost or I go hungry. I realize most people accept and know about the uncertainty inherent in their GPSes navigation – and usually compensate for it with street wisdom. Furthermore, these days most people can simply plug there GPS into a computer program that updates the geographic data on their GPS (and some of these programs even have ways for users to help correct errors). But, in attempting to move us away from the technical side of Hunter and Goodchild, I can’t say I’ve ever seen cells with multiple designations or overlaid error maps on my GPS. Heck, in talking to friends, I was trying to figure out if I’d seen any programs out for common consumption that do this. I mean, wouldn’t it be novel to have my GPS tell me that the restaurant might be at that location give or take a 10 % chance of error?

Not to belabor the point, but I thought one more example might help. In the older days before GPS, I  drove to Boston using Mapquest directions (yes, Mapquest, not the now ubiquitous Google Maps). Unfortunately for me, back then Boston use to always be under some kind of street/highway renovation/construction program. Never, never did my directions get me to where I was going. I almost always got lost and, being a novice driver, very lost. Wouldn’t it have been nice to have been informed about this possible uncertainty in my directions before I left my computer behind at home? Well, my contention is that most of these companies don’t want to admit fault. We instead have to rely on outside Web sites to point out physical, digital and (if you see their post on Brazil) socially-incorrect errors.

I ask you all: Do you know of any programs you use on your computer, phone, GPS, etc. that shows uncertainty/error? How do you think these kinds of companies might be able to work such a feature in? Is it feasible?