Archive for March, 2013

Location Based Services

Thursday, March 14th, 2013

Steinfield’s article on the development of LBS is a nice summation of the technology used, potential applications, and a few of the issues that arise out of LBS services such as privacy. Reoccurring themes that we’ve seen relating to GISci issues definitely include privacy and ethical issues. It’s interesting that a regulation created as a safety mechanism as been exploited for commercial services and now breaches our level of comfort in relaying this kind of information whether intentional or not. To bring it back into the realm of GISci, LBS touches upon topics such as accurate georeferencing, data modeling, and data capturing. While the user’s location is now bought into the forefront, which determines what information is ‘pushed’ or ‘pulled’ to the user, a high degree of accuracy is required of the user’s location and also data being presented to the user. In a navigational system, having the details be a few meters off, or delayed makes the system as unreliable. Similar to AR, LBS is also in real time, requiring dynamic data models that can continually push/pull information specific to the user’s location. This is nontraditional of traditional data models where the user’s physical position did not effect what information was presented in front of them. Another challenge that these types of applications face has to face is collecting, and processing information multiple data sources – though perhaps technical innovation has more or less solved these issues. But how do these systems deal with the massive volumes of GI data and determine which ones should be displayed? LBS and AR is certainly pushing traditional new ways of data modeling and capture.


Like a Memory Lost in Time

Thursday, March 14th, 2013

Langran and Chrisman (1988) covered various conceptualizations of temporal GIS, stressing temporal topology and the need to visualize temporal structure, trap errors, and minimize data storage requirements. In a topic based on the conceptualization of abstract and multidimensional notions, it was enormously useful for the authors to include simple visualizations of the conceptualizations of time, especially in terms of temporal topology (i.e. how events are connected and related temporally).

One visualization of time that the authors ultimately reject as flawed in several ways is that of showing separate “scenes” or “states” in chronological order. I completely agree that this is a flawed practice primarily because of the hidden topological structure of the “states” (e.g. proof that one state occurred before or after another scene, and the interval between them). However, it is also the simplest for a layperson to understand. The authors drew the analogy of a motion picture, and that is significant because films function much as our own memories do, one scene at a time. We cannot capture events in time as anything other than isolated from one another. When we remember an event, we imagine a single image, followed by another and another if the memory is strong. Likewise, those images are from only one perspective—our own. I mention this as a slight digression only to draw a parallel to GIS. Even if we were to adopt the overlay or multi-polygon methods that the authors recommended, we would be ignoring the fact that mapping (at least traditional, top-down mapping) is drawn from a single perspective and that change, the manifestation of time, happens differently from any given perspective.

– JMonterey

Try and Find Me

Thursday, March 14th, 2013

Rao and Minakakis wrote on the current (in 2004) and future state of location-based services (LBS). In their article, they touched on the growing interest in LBS, the requirements for growth, and the types of LBS. While 2004 was not too long ago, nine years is eons for modern technology, and I’m curious how much has changed since. Nonetheless, it is a clear and well-written piece that thoroughly scans over the important aspects of a field that stands at the heart of modern GIS applications.

Until now, my understanding of LBS has been primarily based in how advertisers could market goods and services to targeted individuals who are in an optimal location to be influenced. Thus, my naïveté had resulted in a cynical view of LBS and its exploitative power. However, it is clear that the field encompasses more than marketing; it serves navigation and personalization functions, as well.

Beyond the technical issues regarding positional accuracy, I am also leery of the privacy concerns inherent in any LBS. In the case of personalization, many consumers may opt in to various services for convenience or for a novel experience (i.e. because it’s cool). But there are countless times when consent to be (essentially) “followed” is given as part of something completely unrelated. For instance, Facebook will show advertisements based in the location of the user’s IP address. Considering the easy accessibility of ad-block software, I would not be surprised if advertisers aim for more explicit consent in the future, likely stressing the convenience and novelty aspects of personalization in a positive spin of location exploitation.

– JMonterey

A Temporal MAUP

Thursday, March 14th, 2013

Marceau, Guindon, Bruel, and Marois outline two major problems with the temporal model in GIS: the lack of temporal topology, and the sampling interval. The temporal interval determines the scale at which the geographic phenomenon will be studied, and consequently “may affect the perception of the pattern dynamics of the phenomenon” (p. 4). Ultimately, this leads to Marceau et al.’s explanation that some geographical changes may go undetected.

With this in mind, we can refer to the MAUP in a temporal context. Some trends will be missed depending on the borders of the interval, and false conclusions can be made if a temporal interval is too small or if the full range of years is inappropriate overall. We see this sometimes with global warming — people using global cyclical temperatures since the beginning of time to say that global warming is just another natural temperature trend because there were massive temperature fluctuations way back when. We have to be careful where we put our boundaries.


Moving Beyond Snapshots

Thursday, March 14th, 2013

Marceau et al set out to develop temporal database and analysis functionality in a GIS environment.  They are motivated to do this by the inadequacies of current GIS software to deal with temporal elements, which results in a de facto spatiotemporal analysis approach known as the “snapshot model”: limited to knowledge about specific moments in time with no formal inferences about what happens in between or the process behind any observed changes.

The authors point out two major shortcomings with the snapshot model, the first being a lack of temporal topology.  In temporal analysis, the most important topological relationship is order, or the sequence of events along a timeline, which establishes whether an event happens before, concurrent with, or after another event. Other topological relationships exist as entities appear, disappear and change through time.  Evolving suburban land use is a good example of this, as residential entities may appear in agricultural land, growing and merging into each other until remaining pockets of agricultural use split and eventually disappear.

The other important shortcoming with snapshots is the choice of sampling interval, or temporal resolution, which can have important effects on what events are noted by researchers and thus the conclusions drawn from spatiotemporal analysis.  While even the input data to the article’s case study is basically in temporally coarse “snapshot” form, the authors attempt to address the issue of sampling interval by adding attributes to spatiotemporal land use entities such as “beginning min”, “end max” and “duration max”.  These values incorporate a degree of uncertainty into the model to more transparently deal with the limitations associated with temporal resolution, but I was disappointed to note that there is little here in the way of concrete solutions to the problems of temporal interpolation.

Marceau et al’s model provides a basic framework to harness temporal considerations within the existing vector GIS paradigm.  A key question is whether this approach will be robust enough to be extended into more types of spatiotemporal analysis (such as multi-linear or branching time), or whether we will yet require an entirely new GIS foundation to achieve this.


LBS: Ideas lost to time and tech advances

Thursday, March 14th, 2013

Charles Steinfield’s article, “the development of Location based Services…” is a great summation of location based services (LBS) in the first half of the last decade, however most of the trends and technologies have changed. For instance, the mention of growing “802.11b” wifi networks have gone the way of beta cassettes, mini-disc players and HD-DVDs (all of which I remember using). The article mostly seems to have a historical value to GIScience today, although it does present some of the burgeoning technologies in early generational development we use today in LBSs today. Most of what is mentioned as positioning technology for both indoor and outdoor LBS just seems too impractical and point infrastructure dependent (i.e. Expensive to maintain and maintenance intensive); probably the reason we do not use many of the technologies mentioned.

The application of LBS has matured to a state that any mobile device receives some sort of LBS and the use of LBS has grown beyond Steinfield’s imagination when writting the article. However, LBS although having its benefits, can now hinder what a person is looking for on there device because it provides local services first, rather than the service a user is looking for that may just be out of range.

The belief that Wifi may help LBS was a good point in the article but I believe it is becoming less relevant with 4G mobile networks (and 5G on the horizon) where GPS data in mobile devices (GPS now in all phones) and digital pinging of cell towers are able to communicate, with lightning speeds, resulting in better at predicting of location. That said the idea of security, privacy, and terms of use consent brought up by Steinfield    becomes relevant. Although I think these ideas are concerns, the ability to block location  are restrict location use by the user on most devices (iPhone, most androids) from LBS solves the issues of concern (It should be noted that GPS location services are always available for emergency uses; police, fire, etc.).



visualizing time

Thursday, March 14th, 2013

Marceau et als article looks at the use of temporal GIS in a study of land use in St. Eustache. While the paper shows one way that we may incorporate time into GIS, it is only one fairly limited use. The paper’s twelve year old date is important to consider in a fair critique, and I commend the researchers use of available softwares and interfaces in order to move forward on temporal projects. Further, their goal appeared to be focused on ability to conduct spatiotemporal queries, rather than representation. While the former is probably the more essentially important part of temporal GIS, I’d like to talk about the latter.

The question of how to represent a temporal dimension in GIS is one that seemingly continues to stump geographers, and there doesn’t appear to be strong consensus on best practices. Dipto talked a bit about this below, and I agree with him that a useful area of thought in GIS should be how we might rethink the way we do Temporal GIS. How then might we move forward? Can a static image accurately represent time? And what of that data in between recordings? How can we utilize interpolation that is accountable to the purpose of our GIS?
My main question is: is it important that there be a consensus on representation? And further, what does a consensus mean to us in terms of epistemological and ontological concerns?


Time Goes By, So Slow

Thursday, March 14th, 2013

Temporal mapping has always been one of the biggest issues within the GIS community. Although the visualization of spatio-temporal data has advanced dramatically since the time of writing of the article  (1988), it is still relatively challenging to map and present this type of data in a clear way. Spatial-temporal modeling is useful for many modern day applications. For example, in the field of epidemiology, technologies such as GIS and remote sensing have allowed for the development of models that characterize the distribution of infectious diseases. In addition, these models are also useful for tracking the methods of diffusion of the diseases, as well as how effective containment measures are. Spatio-temporal mapping also holds many important benefits for disaster management, environmental studies, and transportation planning. Overall, further developments within the field are necessary in order to incorporate not only changes over “snapshots” in time, but also the processes that occur in between the steps.

-Victor Manuel


LBS, consent

Thursday, March 14th, 2013

Steinfield’s article on location based services gives a useful overview of prominent technologies, applications and issues related to the domain. Questions of privacy and ethics are raised in the article, but the date of the article means that the most pressing aspects of LBS and privacy have yet to arrive. Indeed it seems that Steinfeld does not forecast the ubiquity of smartphones that we’re experiencing in the present. With current context in mind, I want to briefly revisit some of the questions of privacy raised by the author.

Steinfield cites a set of principles regarding privacy: Notice, Choice, Consent, Anonymynity, Access and Security. With these in mind, I started thinking about what kinds of options we had in terms of communication today. While it is certainly possible to live without a cell phone, it is pretty rare and largely inconvenient, especially amongst my generation. It is expected that we be reachable at all times, and I have heard employment counsellours telling clients that a cell phone is pretty necessary to get a job. I don’t have a smart phone myself, but most of my friends do, and they’ve become a less expensive option than many more basic models of late. But when we opt-in to a smart phone, does that mean we have to (to borrow lazily from Gramsci) consent to our own domination? Is it just that in order to be successful, to be able to communicate, we have to give up a large part of our privacy? Does this model of consent really respect the needs of all parties involved? Does it matter?


Scooby Doo, Where are You?

Thursday, March 14th, 2013

Location Based Services (LBS) have become a major component of the marketing strategies of service providers. With the rapid development of technologies, especially in the mobile arena, it is now easier than ever for providers to deliver focused services. Although Rao does a great job of highlighting the potential of LBS, in reality he underestimates the huge impact it has had since the writing of his paper. Rao predicted that by 2006, LBS would reach 680 million global customers. However, in our modern age of connectivity, LBS is most likely available to over a billion people worldwide.

LBS has and will continue to offer every improving potential to both service providers and customers. Rao highlights some of the advantages of LBS to consumers, who can have access up to date information on maps, driving directions, yellow pages, and locator services. As technology has developed, LBS is now integrated into many everyday applications. For example, consumer applications, such as “find my friends”, allow you to track the exact location of other users (with their approval of course). LBS have also become very important to service providers. With their ability to track a customers geographic habits, they have the ability to tailor business concerns, such as advertisements, that may be more pertinent to the customers interest.

Although LBS hold may benefits, as with many new technologies there are privacy issues. As service providers continue to gather and store huge amounts of location based data, it raises several questions such as- What should be done with this data? Who has access? Is it anonymous?

-Victor Manuel

Radical changes in Time

Wednesday, March 13th, 2013

The paper by Langran et. al. made me realize how little has been achieved in representing the temporal aspect through maps. Digital maps have tried portraying the changes in some phenomenon over time through the use of accessories like time sliders. But this only changes the overlay information on a static base map. The lack of tighter time-map integration makes it impossible to capture the cause and effects in a more holistic way.

Though GIScience emerged as a merger of spatial sciences with technology, it embraced the concept of temporarily static maps to represent data.

The foremost thought that comes to my mind is that a radical change is required in how we represent space-time. The whole concept of maps needs to be redesigned to break the triangle of theme, location and time. Though this may be a very strong statement without much backing, I think with redesign of representation and choosing the right data structure, maps can be made to represent both location and time together, keeping the theme fixed. This will be akin to perceiving the world as a state machine, with a set of states and actions that causes state changes (but the set of states and actions may be potentially infinite and not necessarily be known a priori). The concept of state machine addresses the “root” of the problem, i.e. different snapshots represent the states, but not the events that caused the changes. This however, requires tremendous efforts and change of mind-set coupled with embracing of technology in redesigning the thought process.

– Dipto Sarkar

Faith in VGI: Easy Come, Easy Go

Friday, March 1st, 2013

Coleman et al review developments and issues in the emerging realm of volunteered geographic information (VGI).  Focusing on VGI as a crowdsourcing exercise, the authors create a typology of users (they coin the term “produsers” to describe the ambivalent status of VGI participants) based on experience level and familiarity with the topic, ranging from the “neophyte” to the “expert authority”.  They then create another typology for contexts of VGI procurement: “Market-driven”, “Social Networks” and “Civic/Governmental”.

One of the produser roles that most interests me is the “Expert Amateur”, someone who is very knowledgable about a topic or locality but is not employed in the field.  I forget whether it was this class or 407 (or maybe I just need sleep), but I find the possibility of making spatial references out of unstructured urban planning discussions as per a Ryerson University case study a great application of VGI.  There are many webforums out there like SkyscraperPage that are overflowing with discussions and ideas about how to improve users’ hometowns, but no broad audience for these discussions.  A broader airing of these ideas could take place if they could be mapped, helping these expert amateurs to more effectively help the communities they care about.

An important and emerging issue in VGI that the authors do not appear to cover is the use of passive VGI, when geographic data about users and their content is collected (e.g. by phone companies or social media services) covertly.  Clearly, there are ethical and privacy issues associated with such practices. The potential for VGI to be a tool of engagement and empowerment will disappear as quickly as it has emerged if produsers’ faith is undermined by the sneakier and less transparent nature of passive VGI.

– FischbobGeo

Mental Maps and Cognitive Space

Friday, March 1st, 2013

Tversky et al describe and discuss humans’ cognition of space at three different scales: that of navigational space, the space around the body, and the space of the body itself.  They review studies that have demonstrated that humans’ mental representations of these three spaces are both schematicized, or simplified while maintaining topological relationships, as well as distorted in important ways.

I’m aware of geographic research dealing with the scale of the body and its surroundings, but I think the most operational of the authors’ scales for most geographers is navigational space.  Speaking personally, it is my proficiency in navigating that likely made geography an attractive field of study for me coming out of high school.  Yet even experiencing navigation as second nature, I am struck by how much even my own mental maps bear the marks of schematics and distortions.  My hometown I know fairly intimately, and I have memorized most of its street network and important landmarks: and even here, I am not so concerned with the precise positions of particular locations in Euclidean space as I am with how they fit into my view of nodes in the spatial network.  Though various neighbourhoods’ street grids are rotated in relation to each other based on the local topography, in my mind they are brought into alignment and the primary transportation axes from “south” to “north” in the city appear as straight lines to me, despite their many twists and turns in reality.

Though I have worked less with the other two cognitive spaces discussed by the authors, I can readily see important applications for them in emergent GIS tools: namely, there is a need for tech such as Google Glass to integrate navigational space functionality, an AR/HUD environment in the space around the body, and the HCI input systems using the space of the body.  A more nuanced understanding of how humans understand each of these spaces will be incredibly helpful for making more user-friendly and intuitive gadgets.

– FischbobGeo

Spatial cognition, ontology, epistemology

Friday, March 1st, 2013

Tversky, in his paper, divides spatial cognition into three “spaces”: navigation, surrounding the body, and the body. Reading this article brought to mind previous discussions in our classes with respect to ontology and epistemology. While the article gave a series of examples of each type of spatial cognition, they were mostly rooted within a Western Academic framework. It would be interesting to extend this discussion of spatial cognition to the ways in which it is variable.
I think that the way we think about space is highly structured by our environment and culture. That is to say that the way we order the environment is culturally located. The space of navigation is an easy place to see this difference. I remember in an earlier GIS class talking about the house numbering system in Japan. Wikipedia explains:

“In Japan and South Korea, a city is divided into small numbered zones. The houses within each zone are then labelled in the order in which they were constructed, or clockwise around the block. This system is comparable to the system of sestieri (sixths) used in Venice.”

Even this small detail will have bearing on the space of navigation. While I feel confident navigating the Canadian street system, I would be lost in this different system. I think that it would require that I think about space and spatial relationships in a new way. My spatial cognition is rooted in local understandings. Thinking of this in terms of GIS work, I think it is important to keep in mind the ways that we think about space in our work and how that accords with the people we are producing GIS with and for.


Volunteered geographic information

Friday, March 1st, 2013

This article presents volunteered geographic information (VGI) and provides some interesting and new examples of implemented tools using spatial information that has been donated or provided by citizens informally, such as OpenStreetMaps, or data that have been altered (e.g., the John Snow map, which is super cool). I think the primary issues that arise when people discuss VGI are privacy and accuracy. By privacy, I mean that people tend to be concerned about “volunteered” information and whether the users truly understand the potential ramifications of sharing spatial information. By accuracy, I mean the same concerns that surround citizen-based websites like Wikipedia; even though scientists and students use Wiki entries for reference on a maybe daily basis, and even though it is likely the go-to reference for lay people as well, it is a standard practice to reference alternate sources which confirm the same facts. Alternate sources, written by experts (potentially the same experts who wrote the Wiki entry), are considered superior in accuracy because they are not written by an “average citizen.” I think my ideas here are related to what Wyatt discusses in his post – that there might be some irony or plain incorrectness is assuming that a paper in a journal or a book chapter is more accurate than something in a Wiki entry. We all believe this, or at least participate in it (by never citing Wikipedia, while constantly using it), and it’s interesting that while a paper may have been repealed or a textbook may be out of date, a website like Wikipedia is a dynamic, updating realization of current opinion. Is it subject to error? Absolutely, but like Wyatt pointed out, so is everything else. I think these ideas need to be challenged to some degree, and I think geographers and those trained to value spatial information are in a good place to discuss this. What is desirable and not desirable in spatial data, what is “good” data, and who decides?