Saturday, September 10, 2011
Reaction:Distributed Cognition as a Theoretical Framework for Information Visualization
Reaction :Attention and Visual Memory in Visualization and Computer Graphics
Reaction:External Cognition: how do Graphical Representations work?
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
I agree that systems should have measurable metrics that allow us to determine a system's usefulness. The authors make it seem that it is nearly impossible to come up with standard guidelines that can be used among different systems. If these standards were to be achieved, would results be consistent after repeating test trials using different people?
Overall, I think that the DCog framework for developing InfoViz systems is a good step toward standardizing the field. It provides a different perspective on the evaluation of tools created in the InfoViz field.
Friday, September 9, 2011
Data: CIA World Factbook
App Smart Extra: CIA World Factbook Apps
The Central Intelligence Agency's World Factbook, a free global reference book, is available on smartphones through a variety of apps.Data: Excavating Your iPhone's Past
Excavating Your iPhone's Past
After a glitch erased my iPhone, I found a way to extract all my old text messages.Thursday, September 8, 2011
Tutorial: Geographic data on a map with Python
via Seeing Data by Chris McDowall on 8/11/11
Last week I promised to write a blog post detailing how I created this public transport animation. On reflection, it’s a topic best dealt with over a few sessions. Let’s start simple. How might you plot lots of geographic data on a map? In this post I will show you how to programmatically create a map of the World’s top ten most populated cities. It will end up looking something like this.
Competition: visualizing marathon
Announcing two big updates to the 2011 Visualizing Marathon Program: the New York's Marathon dates are now November 5-6 and the Germany Marathon will now take place in Berlin (December 3-4).
We’ve had a great response from both students and schools in all of the Marathon locations and we have two big updates to the 2011 Visualizing Marathon Program.
Due to Yom Kippur and the Columbus Day holiday, we’ve changed the dates for the Visualizing Marathon competition in New York to November 5-6 so that everyone can participate. We are still planning the same great event, just for a different weekend.
Data: bit.ly API
We are pleased to announce some new user-level metrics features in our API, making it even easier for developers to provide bit.ly users with realtime feedback about their trending bit.ly links.
We are currently using the new /v3/user/realtime_links API endpoint in our Chrome Extension to notify bit.ly users about their “Trending Bits.” This feature provides a popup notification whenever one of a bit.ly user’s links receives a certain number of hourly clicks. (This threshold can be modified within the extension’s settings.)
Other user-level metrics endpoints provide an overview of click traffic, referrers and originating countries across all of a bit.ly user’s links. All of these user-level metrics endpoints are accessible via OAuth 2, making it easy for users to access their bit.ly data via third-party applications without having to enter their bit.ly API key, username or password.
These new API endpoints and our OAuth implementation are fully documented at api.bit.ly. If you have any questions, do not hesitate to contact api@bit.ly, or sign up for the bit.ly API Google Group.
Viz: Access to Wikileaks
This Wednesday September 15th at 6pm, we will open the doors to our New York office for our third monthly hackabit hackathon! Our first two hackathons spawned lines upon lines of JavaScript, Python, C, Haskell, R, and many other delightful languages. A Wikileaks data visualization project from last month’s hackabit ii even got a shout-out in the New York Times bits blog.
This month’s hackathon promises to be particularly action-packed, as we will be rolling out some awesome new metrics-related bit.ly API endpoints. We will be holding another API contest in the near future, so be sure to come by if you want a head start!
If your project isn’t bit.ly-related, have no fear - all code is good code at our hackathon. Come hack, snack and throw back (some energy drinks) with us! Click here for more information and to register - we hope to see you there.
Data: Links Followed to Govt Sites
Do you know exactly what you were reading 10 years ago this very moment? 10 years from now, you may. The data we create is a living archive of our interests and intentions, and we’re creating more of it every day — a staggering 1.2 zettabytes last year alone. At bitly, we are always looking to learn from our data, and we are thrilled that a particularly interesting set of bitly data is being made publicly available for hacking and analysis.
This Friday evening, bitly will host the New York branch of a nationwide, 4-city 1.USA.gov open data hackathon. The USA.gov team has made the realtime clickstream data for all 1.USA.gov URLs open to the public, providing an unprecedented window into the way that we engage with government content. We are extremely excited to see what talented hackers and coders can do with such a rich and fascinating data set.
In advance of the hackathon, the Measured Voice team has put together a microsite at govclicks.measuredvoice.com that ranks the most popular 1.USA.gov URLs per day by click count (an average of about 56,000 total daily clicks over the last few months). The diversity of content at the top of the list is fascinating; a NASA Tweetup announcement alongside information about the recent FAA furloughs and a strongly worded FDA warning to Diamond Foods about walnut packaging.
This basic ordered list provides a compelling look at the popularity of specific government URLs – and it is only scratching the surface of the underlying data. Where in the country are most people looking up information about FAA furloughs? (And, using a complementary API like SimpleGeo’s Context, what do we know about the demographics of those regions?) Which social networks drive the most traffic to NASA’s website? What US government content is most frequently accessed outside the US? There’s a wealth of insight encoded in the 1.USA.gov data just waiting to be discovered.
Indeed, working with data isn’t just a matter of crunching numbers and writing code; it also means knowing what you’re looking for and knowing what you’re looking at. Through the right lens, the data from the 1.USA.gov project could answer questions that we hadn’t even thought to ask – and some of the data that answers those questions may very well be yours.
If you’d like to explore this data with us, then come to our NYC office this Friday (or visit the other 1.USA.gov hackathons in San Francisco, San Diego and Washington D.C.) and build something new!
Viz: USA.gov Hackathon results
Many thanks to everyone who came out to our 1.USA.gov hackathon! It was great to see so many friendly hackers and open data enthusiasts collaborating and sharing ideas (and devouring 11 pizzas in about as many minutes).
Our friends at USA.gov posted a summary of the hacks created at all four nationwide hackathons, including an awesome visualization of NASA’s popularity worldwide created by Adam Laiacano at our New York office. Here are a couple more hacks that came out of the New York hackathon:
* A fascinating set of data visualizations by Harlan Harris.
* Sonification of 1.USA.gov data by Niki Yoshiuchi.
Want to hack on the 1.USA.gov data? It’s still publicly available on the USA.gov website. We’ll be hosting another hackathon soon — keep an eye on the hackabit Meetup group for more information!
Viz: Half-life of shared links
How long is a link “alive” before people stop caring? Does it matter what kind of content it is, or where you shared it? At bitly we see a lot of links, and while every link is special, we’re learning a few general principles that we can share.
Let’s take a look at one particular story - Baby otter befriended by orphaned kittens - which was first shared by StylistMagazine on Facebook on Tuesday at 7:12am. If we plot clicks over time for this link, we see:
Rate of clicks per 10 minutes on “Baby otter befriended by orphaned kittens”
We can evaluate the persistence of the link by calculating what we’re calling the half life: the amount of time at which this link will receive half of the clicks it will ever receive after it’s reached its peak. For this link the half life was 70 minutes, which captures all the clicks between the grey lines on the graph above.
Let’s look at a second link - East Coast earthquake: 5.8 magnitude epicenter hits Virginia - , this one first shared by the Washington Post on Twitter.
Rate of clicks per minute on “East Coast earthquake: 5.8 magnitude epicenter hits Virginia”
While the exact details of the traffic are a little different, and the scale of the traffic to this link is much larger, we see essentially the same pattern: a fast rise, and a more relaxed drop-off. Noticeably though this link a half life of only 5 minutes: after 5 minutes this link had seen half of the clicks it would ever see.
This link is associated with a very timely event (an earthquake on the US East Coast) as opposed to the previous link (pictures of otters and kittens are clearly interesting all the time). We think that this difference in content drives the difference in dynamics of these two links. However, one alternative theory that comes up again and again is that the dynamics of the link traffic depend on where the link is posted: do links posted on facebook last longer than they do on twitter?
So we looked at the half life of 1,000 popular bitly links and the results were surprisingly similar. The mean half life of a link on twitter is 2.8 hours, on facebook it’s 3.2 hours and via ‘direct’ sources (like email or IM clients) it’s 3.4 hours. So you can expect, on average, an extra 24 minutes of attention if you post on facebook than if you post on twitter.
Distribution of half-lifes over four different referrer types. Facebook, twitter and direct link (links shared via email, instant messengers etc.) half lifes follow a strikingly similar distribution.
Not all social sites follow this pattern. The surprise in the graph above is links that originate from youtube: these links have a half life of 7.4 hours! As clickers, we remain interested in links on youtube for a much longer period of time. You can see this dramatic difference between youtube and the other platforms for sharing links in the image above.
The graph shows the distribution of half lifes for each referrer. So we’d expect to see link half lifes of less than 20K seconds (5.5 hours) for facebook, twitter and links shared directly, and we’d be very surprised to see any link maintain significant traffic for a lot longer than 60K seconds (16 hours). But for youtube, we’d be a little surprised to see half lifes of less than 5 hours!
In general, the half life of a bitly link is about 3 hours, unless you publish your links on youtube, where you can expect about 7 hours worth of attention. Many links last a lot less than 2 hours; other more sticky links last longer than 11 hours over all the referrers. This leads us to believe that the lifespan of your link is connected more to what content it points to than on where you post it: on the social web it’s all about what you share, not where you share it!
This post brought to you by the bitly science team! Questions or comments? Email us.
Data: Fusion Tables, a New Google Docs App
Fusion Tables, a New Google Docs App
Aaron, a reader of this blog, spotted a new option in Google Docs: creating tables. It seems that Google Docs started to integrate with Fusion Tables, a little-known Google service that lets you manage large data sets.Tool: New features and a new home for Swiffy
New features and a new home for Swiffy
By Pieter Senster, Software EngineerTool: Google APIs Client Library for PHP (Beta)
Google APIs Client Library for PHP (Beta)
Viz: An Interactive Timeline of London Riots
The interactive visualization from the guardian shows the occurrence of various events from the start of the riots till the cleanup process. The map is divided into columns based on various areas and important aspects like police and social media. The timeline below can be dragged to view the series of events. The markers and their color indicate different types of events.
The visualization can be seen here:
http://www.guardian.co.uk/uk/interactive/2011/sep/05/england-riots-timeline-interactive?CMP=twt_gu
Reaction: Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods
Wednesday, September 7, 2011
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
As the discussion moves to the visual memory aspect, some of the very interesting points are put forward. Firstly, human vision is far different from video cameras. Rather than creating a high resolution image, it creates an abstract view. The view changes only when significant changes occur and they get attended by the vision. The topics Change blindness and Inattentional blindness make an interesting read. Another point to be noted is that, some of the details are stored in the memory but can't easily retrieved unless explicitly asked for.
Finally the author spends some time in describing how the previously mentioned theories can actually be implemented in practice for visualizations and graphics. The author also mentions challenges in designing effective visualizations. This paper is surely an interesting and informative read for everyone who wish to build effective visualizations.
Reaction: Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods
Every graph is presented with the reasons behind using it for a particular data set. I find that this is an important point which was mentioned in the paper so that the reader can understand the usage of different graphs. The paper was also very simple to read and understand and I learned new concepts like the bar and framed rectangles and also found the position angle experiment very interesting.
The experiment that was conducted with a group of people co-relates to real life experiences and this helps the reader in remembering the ideas which are presented in the paper. I also found the framed rectangle chart very useful because it helps us present statistics using a black and white coloring without the black color dominating the white one. I thoroughly enjoyed reading the paper and would certainly extend my knowledge by reading some of the references mentioned in the paper.
Tool: Google Correlate
Google Correlate is a tool from the google labs that gives similar search patterns based on the uploaded dataset or a drawing. We can get the results based on a defined time line or US states.
We can see the tool here:
http://www.google.com/trends/correlate/
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
In many ways, I think the authors' argument that DCog provides a more useful frameworkto address the central issues of representation and interaction than does the traditional cognitive science frameworks, is valid. Attributing the cognition aspect totally on the human individuals, in many ways seem to me as an improper model of the actual process of visualization of the information.
We should realize that distribute cognition, can be found in our daily activities. For example, when a couple of people are trying to understand a complex algorithm. The persons share their thoughts and approach towards the problem, and may further use the paper and pencil to write down their understandings and successfully reach to the solution of the problem.
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
The main objective of the paper is to shed light on visual perception .i.e., how people look at an image and what they learn from it. The paper performs deep analysis of what is known as "preattentive processing" - data learned from a small portion before an eye movement occurs. The paper states that what we see depends on what is on our minds. But human mood is known to change, does changing mood affect the way we see things? The paper presents several models on preattentive processing which are all hypothesis. It would have been helpful if experiments were stated on these models to give them credibility.
In one of the models by Treisman, the properties that were preattentive were determined. But the paper does not state the method in which they were determined. I was left wondering if this was done scientifically or through a survey. One feature described in the paper, ensemble coding, was particularly interesting. It showed that it was easier to compute averages than remembering specific details. The amount of information present in the paper is staggering. A lot of concepts had correlation to each other which was not evident in the first reading.Reaction: Attention and Visual Memory in visualization and computer graphics.
The paper starts with explaining the phenomenon of Preattentive processing. It is interesting to know that fixation-saccade cycle repeats 3-4 times each second of our waking lives, and all this is totally involuntary, without any awareness.
Then the authors go on to present number of theories which attempt to explain how preattentive processing occurs within the visual system. All these theories have focused on how low level-visual processes can be used to guide attention in a larger scene and how viewer's goals interact with these processes.
I think in order to understand and delve into the concepts of information visualization, it is very essential that we understand the science behind the visual memory and human perception. The research in this direction will help how physical resolution and visual acuity affect a viewer’s ability to see different luminance, hue, size and orientation values.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
The paper is an attempt to provide substance to the foundation of InfoVis using Distributed Cognition. The traditional belief is that cognition is information processing inside the brain. The paper states that the above belief is misplaced. It states that the environment plays an important role in shaping human cognition. A scenario is depicted in the paper in which an analyst interacted with an interface through a technical person. The scenario showed that processing of internal data is tightly bound to the processing of external data. Would the binding be more lenient if the analyst had used the interface himself?
The paper states that the transformations of external representations are visible but the transformations of internal representations are depicted through individuals in a cognitive system. This statement sounded skeptical and not entirely credible. DCog focuses on the inter dependency and coordination between between people and environment.But what if we have a system where individual properties are also important?DCog is still a framework which cannot be applied to issues in InfoVis as of yet. So, there are no concrete assurances that the theories presented in the paper can be materialized.
Reaction: Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods
This paper attempts to establish a standard for data analysis and presentation using graphical methods. The paper is legible because it uses examples to test and prove its theory. The paper states that alternative graph forms (dot charts) were used instead of popular graphs (bar graphs). The reason for this seemed unclear while reading the paper. I couldn’t understand what radical surgery was. The paper produces guidelines to be followed when constructing graphs to achieve maximum cognition. These guidelines’ are inferred from the perceptual tasks performed by people as they understand the graph.
10 perceptual tasks are initially identified. The paper narrates how these tasks aid in extracting quantitative information from several kinds of graphs with visual examples. The tasks are then ordered for maximum efficiency in graph perception. The authors initially hypothesize that judging length is more accurate than judging area which in turn is more accurate than judging volume. This hypothesis is believable to a reader when he looks at the examples and tries to judge for himself.
Reaction: Graphical Perception-Theory, Experimentation, and Application to the Development of Graphical Methods
As the name itself suggests this paper presents set of theories and experiments related to presenting the large amount of data in manner which provides more information. It suggests how we can improve the information presenting qualities of the traditional graphs. This paper has been fairly comfortable to read and understand because of the ample amount of examples and explanation provided for each theory and experiment. I like the experiments where it tells the situations wherein different types of graphs could be best fit. Length judgment in bar graph, angle judgment in pie chart and things like that were new to me. I thing i liked best about the paper was that the experiments correlate much more to real life situations. In sum, the paper did a really good job at explaining its theories, method of experimentation, expectation and results.
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
I liked reading this paper. One of the main reasons for this is that it's much easier to recognize, understand, and learn from something you could correlate with. The ideas presented in this paper where more close to real life situations. The main focus of this paper was how we perceive visualization. It was good to learn about how the human eye processes visual images or other information. It was rightly said that the user only concentrates on the piece of information he wants to notice and thereby ignoring other relevant information which might be present around. Overall, it was a good paper to read but I would like to read more stuff about the utilization of visual attributes in the infoviz world.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
This paper was bit different than the others we have read so far. It presents a different perspective while showing the inefficiencies of traditional cognitive science when it comes to information visualization (info). But unlike other papers this one presents a theoretical framework for Distributed cognition. Personally this paper was bit difficult to digest and required reading some part over and over again. I was also thinking about the practical usability of the framework because as of now it is not fully developed.
I liked the use of basic examples throughout the paper but at the same time it made it difficult to generalize the concept for a broader use. Since there hasn't been much research in the field of cognitive side of visualization, at the moment this paper looks more abstract without supporting implementation. Also it does not provide much support to why DCog is more effective framework than the traditional one for information visualization. But as a whole it is a good paper to read in order to start thinking in a new direction something which is not in practice yet.
Reaction:Graphical Perception:Theory, Experimentation and Application to the Development of Graphical Models.
graphs and graphical perspective. The ordering of elementary tasks and
placing them as high as possible in the hierarchy allows the
visualizations to be perceived properly by the user. The author
compares the existing representations of data and provides a better
results if the graphs are constructed keeping in mind the graphical
perception.
processing and distinguishes the date. The transformation of various
graphs depending on the type of data to increase their understanding
is very impressive and changes the opinion on how we think about the
data. the paper suggests not to use particular types of models but on
what types of models can be used for different data in a general view.
Reaction: Distributed Cognition as a Theoritical Framework for Information Visualization.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
But I personally believe the authors have not been able to achieve whatever was stated in their proposal. Some of the point where in they sight examples of Hutchins that writing reading and interpreting a task with tools does not involve much of cognitive amplification is understandable and it proves that its is composed of individuals and the artifacts they use to accomplish a task (which is Cognitive system).
Even though the authors are trying to prove DCog(Distributed Cognition) they were not claiming that its more correct than traditional cognitive science. The author here has done a safe play by avoiding to completely rule out the traditional aspects and have tried to prove that its should be refined and may be DCog is the suitable theory.
The experiments on Osakas butterfly smuggler which says that factors like notepad, software and infrastructure affect the cognition was interesting read. Examples on distributed representation of oranges, donuts and coffee similar to the tower of hanoi was very intuitive. From these examples the authors were able to convince that cognition does depend on other factors. Since the theory itself is abstract and emerging a detailed study is required to understand the topic and may be as the author says DCog could be a theory which will formalize InfoVis.
Reaction: Distributed Cognition as a Theoretical Framework
Reaction : An experiment in graphical perception
It mainly focuses on these
(1) Position along a common scale.
(2) Position along identical but non-aligned scales.
(3) Length.
(4) Angle.
(5) Slope.
(6) Area.
There is an experiment conducted focusing on these aspects and how it matters.
The experiments in graphical perception help in improving the display of data.
It shows that by our choice of the graphical methods we use to show data, we can control,to some extent, the basic judgments that are required to decode quantitative information.
Reaction : Attention and Visual Memory in Visualization and Computer Graphics
There are a few theories related to "preattentive" processing which show us various ways in which our visual memory behaves by illustrating though various examples.
Visual attention is particularly important as it can be used to track the observers attention. Particularly we are often wondering what should be highlighted or underlined in a page, this is the key in drawing the visual attention.
There are a lot of details about various kinds of pre-post attentive aspects , the current challenges part offers a very interesting question : " What is the information-processing capacity of the visual system" ? , I think although we can clearly identify few of the ways in which the visual attention and perception of few known things, it is still a difficult subject to determine the capacity or the processing of a visual system.
Reaction : Distributed Cognition as a Theoretical Framework for Information Visualization
substantiate the theoretical foundation of InfoVis. The author tries not be arcane by providing a lot of analogies and examples, he quotes brief history of time, butterfly example,tower of hanoi and even touches greek phisolophy and its philosophers like aristotle. At times where is attempting to simplify and articulate his views by using analogies and examples, at times they are digressing.
The conclusion although again starts with history and lessons to be learnt from it , is the best section. It gives a good summary of how the field is new and would require time to establish the theories. InfoVis is closely related to Human perception and cognition. The also argues that DCog provides a more useful framework in representation and interaction which the tradi-
tional cognitive science framework do not in comparison.
Reaction: Graphical Perception: Theory, Experimentation, and Application to the Development of Graphical Methods
Reaction: Attention and Visual Memory in Visualization and computer Graphics
This paper discusses the importance of human perception in visualization. The paper talks about preattentive processing where humans automatically tend to categorize an image into different regions or different properties.
Dr. Healey presents visual examples to understand how they are perceived by humans, based on colors, shapes, boundary margins and the mix of these or other properties. He uses this to form the basis of his discussion in the paper where some features like a unique target or a different boundary are declared to be preattentive. The author describes the various scientific theories that explain why and how such preattentive features are categorized or identified quickly by the human visual system.
I specially liked the theory of feature hierarchy where the author talks about how certain elements help in presenting info without any confusion as some features are more prominent or so very distinct from another that the visual system can easily perceive it. Also, it is very interesting to know about how the human eye searches for color, text and how sometimes it is blind in identification of some changes, how memory plays an important role and how the mood of the person just before seeing the visual or repeated viewing of the visual can change his perception and understanding of the information.
This paper describes the theories and the many factors that affect visualization and perception. I wish it had included details of how a visual/ graph design can incorporate these sensitive issues to present maximum information to the user in a glance.
Reaction: Graphical Perception - Theory, Experimentation, and Application to the Development of Graphical Methods
In this paper author approaches the science of graphs through human graphical perception. Their approach includes both theory and experimentation to test it.
To test the above, two experiments were run in which subjects were supposed to judge bar and pie charts. For each type of judgment, subjects made visual evaluations and the result of the two experiments substantiated the theory i.e. position judgments were more accurate than length judgments and angle judgments.
Using the Bootstrap tool, author examined the sampling distribution of the error means and proved his experiment by giving mathematical justifications also. One good thing about the paper is that even after the authors have justified their theories/experiments, they stress on revising the theory as new experimental data is collected. The paper not only presents the graphical forms, which are used in data presentation but also in data analysis. Triple Scatterplots is one such tool for comprehending the structure of 3-D data.
Another impressive thing about the paper is that all the graphs and charts are so coherent and unambiguous instead of displaying pretty much data.
According to author, inspite of this theory having some limitations, it has produced very good results. Its application to some of the popular charts in graphical communication has led to replacements. The paper says that we should keep proceeding in the field of graphics and to do so, must be prepared to discard the old methods with the new and better ones.
Reaction: Attention and Visual Memory in visualization and Computer Graphics
Tool: inMaps
Reaction: Distributed Cognition as a Theoretical Framework for Information Viz
Reaction:Attention and Visual Memory in visualization and computer graphics
All the papers till now have explained the benefits of visually displaying information and the different ways in which it can be represented. This paper deals with the actual science of visual memory and attention explaining how our visual memory reacts to different images.
I have seen this paper a couple of times. In fact Dr, Healey himself showed this paper in class when I took computer graphics under him last semester. The paper begins with the concept of preattentive processing. Various examples are given to prove how it becomes difficult for our visual system to spot the red spots when surrounded by red squares and blue circles. Then the paper deals with some theories of preattentive vision. The part that deals with changed blindness and inattentional blindness was eye catching. It was so very difficult to spot the difference between the two images when they were flickering. Unless your eyes are at the exact spot of difference, you wouldn’t be able to see any difference between the two images.
I think to be in the field of visualization it is very important to know the science and various theories behind the visual system, how are visual system reacts to different surroundings, how long is the attention span and why the system fails to distinguish between objects when surrounded by similar hue and shaped objects.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization"
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
Reaction: Graphical Perception: Theory, Experimentation and the Application to the Development of Graphical Models
Reaction:Graphical Perception - Theory, Experimentation, and Application to the Development of Graphical Methods
The experiments in the paper focus on ordering of elementary perceptual tasks based on the accuracy of extraction. The experiments clearly show that length judgement in bar graphs gives better accuracy compared to angle judgement in the pie charts. The accuracy of judgement also depends on the positioning of the elements.
The author extends this conclusion further to state that, certain non-traditional graph types like dot charts, framed rectangle charts etc are better for design of graphs. However, no experimental proof is given for this. It should be noted that, in the experiment described in the paper compares two well established, traditional graph types. It should be interesting to see result of similar experiment performed with bar charts and the dot charts. Results of such experiments will give us an idea whether human brains respond more accurately to a traditional representation or to a representation which is easier for perception.
Reaction : Graphical Perception
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
The author draws differences and explains perception and cognition. Perception is the way humans see things; cognition, the way information is processed. Thus perception is followed by cognition. InfoViz has developed with respect to quick perception of data but there is no benchmark that can measure cognition. All in all the author tells us how InfoViz could be enhanced if we have a framework for cognition. However the paper fails to present a framework itself. Thus unlike previous papers reviewed today this study does not seem to give concrete results that can be used to bring tangible benefits to the field of Visualization.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
Reaction: Attention and Visual Memory in Visualization
Reaction: Graphical Perception
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
Reaction: Graphical Perception- Theory, Experimentation and Application to the development of Graphical Methods
Reaction: Attention and Visual Memory in Visualization and Computer Graphics
Dr. Healey presents the various stages in which a user interprets images. There is a pre-attentive visualization which gives us information reflexively. The user interprets this information sub-consciously without actually observing the representation. Many factors in a visualization play important role in this. Color, dimensions, position to name a few. This point is proved by the snapshots of the experiments that are included in the paper. One can find more intuitive examples on Dr. Healey's web page. The snapshots in the paper come from the applets that have been included on his page. Further the paper presents various aspects like postattentive amnesia, memory-guided search, change blindness, inattentional blindness, and attentional blink. We come across these things in our daily life but we seldom know what these are called or what is the reason behind these phenomenon. This paper does the job of conveying a reader a study of why these things happen. By using this knowledge we can better visualize data and thus convey it better to an end user.
Reaction: Distributed Cognition as a Theoretical Framework for Information Visualization
Reaction: Graphical Perception- Theory, Experimentation and Application to the development of Graphical Methods
In my opinion, this is a well written paper with a few good points and bad points. Good points being the care with which the author carries out his experiments. Details like experimental environment, choosing subjects, hypothesis, studying results are taken good care of. This is a sign of a good scientific study. However overall the paper seems outdated. The enhancements proposed to the most basic graphs have not been in practice since the paper has been written and still these graphical representations have come a long way. So reading the paper today gives me an impression that their effort was futile. To conclude I think graphs, pie charts, etc. are to give an overall representation of the data and to gain accuracy the user will have to refer spreadsheets and databases.