Much preprocessing was needed before visualization. First, we have to coalesce the keywords, for example, we manually group "hierarchy" and "hierarchies" as the same keyword. Next, we find the most important keywords, with the most number of papers. We use these keywords as research areas within information visualization. We also notice that many of the 2002 papers do not have keywords, so we have to manually insert keywords according to their titles. We are not allowed to look up external information, that is, we cannot find their actual keywords from the publication. Next, we re-arrange the areas using MDS such that those areas with the most cross-references are placed near to one another. Since there is so much data, we find the important papers/authors, according to how much they are cited, and we emphasize them in our visualization.
In this one image, we show a lot of information, for example, (1) important keywords and all the papers under them, (2) related research areas (eg. graph is next to hierarchies), (3) citations, (4) references, (5) authors, (6) important authors, (7) important papers, and (8) important external papers. A key design feature is that all these very different information can be visualized clearly in one single display, without confusion. The way this is achieved is through color-coding, so that if any user is interested in any particular information, he/she just has to focus attention on that color. For example, if you focus on the cyan words, you see all the first authors, and everything else fades away (try it out yourself!).
On the other hand, this same image is able to give an overview of the history of the Infovis Symposia. To this end, the user simply puts mental focus on nothing in particular, and obtains a general impression of the data.
The important papers are represented by bigger circles according to how many citations they have within Infovis. Their titles are also labelled. The two most important papers also have their citations highlighted. In this way, the important papers are immediately visible. We can see that the top two papers are both in the earliest year (1995), and they are also in two very different topics, since they only have two common papers refer to them.
The layout consists of vertical grey columns of research areas within Infovis. The areas that contain more papers are thicker and are labelled with darker text. We can clearly see that the most important area is "hierarchies" and this area contains many recent papers.
We can also see the authors, especially the important authors. We will describe this insight in more detail in Task 3. Other information presented in this visualization are the references, and also the most-referenced external papers. There are many references within Infoviz, especially in closely-related areas like graph drawing and hierarchies. There are also many references within the same research area, such as within information retrieval, graph draing, taxonomy, and hierarchies. Two of the most important external papers are related to tree visualization, so they are cited a lot by papers in hierarchies.
Summary Visualization of the IEEE Symposia on Information Visualization from 1995 to 2002 using One-For-All, a tool by Soon Tee Teoh and Kwan-Liu Ma.
Optionally, the user can choose to display less information at once. This is can be easily custom-made according to the information the user is more interested in, and according to the user's tolerance. This particular image removed the line representing external references and authors' names (except for important authors).
We can see basically the same information as before. One thing that has become clearer is the visualization of the important authors. We can see for example that author Wijk is very active in the research area of hierarchies.
Papers which do not fall under the top categories of research areas have their positions placed in the white areas, and labelled according to their keyword. Their position is determined automatically by their references, to minimize distances. We can see that there are two clustering papers optimally placed next to data mining, and we know that these are related areas.
TASK 2: Characterize the research areas and their evolution
- Process:
The research areas and their evolution can be seen more clearly simply by removing some extraneous information from the visualization. - Image 2.1 :
- Insight 2.1:
Hierarchies is a very strong research area, with more papers in recent years. Graph drawing particularly has many papers in 2001. Information retrieval has many papers early in 1995, but no papers in recent years. Adjactent to Information retrieval is Information analysis, which has many papers from 1996 to 1999. This is interesting because analyisis logically follows retrieval, so it makes sense. Although these two research areas don't reference each other, it is interesting that MDS places them next to each other.
TASK 3: The people in InfoVis
Task 3.1: Where does a particular author/researcher fit within the research areas defined in task 2?
- Process:
This information can be obtained from looking at the overview display. However, to get an even clearer picture, we once again get rid of the unnecessary information. To see the place of a particular researcher in Infovis, we color-code the author. We divide the circle representing each paper into segments, one for each author. The segment will be colored by the author highlighted. Since the papers are positioned by their year and research area, these information are immediately visible. - Image 3.1.1 :
- Insight:
G. Robertson: G. Robertson is colored red. From the display, he is responsible for one Infovis paper that doesn't fit in any of the major research areas we identified, and he is also responsible for one of the top 3 external papers.
M. Chuah: M. Chuah is colored light green. From the display, she is responsible for papers in many different areas. More about this in the next image.
A. Keahey: In contrast to M. Chuah, A. Keahey is very focused on one research area: focus+context visualization. Over the years, he has three papers in under this category, and none in other categories. We can very quickly notice his papers in one column. - Image 3.2.2:
- Insight:
Here, we highlight the author M. Chuah. Looking at the titles of the five papers, they are indeed in very different research subjects.
Task 3.2: What, if any, are the relationships between two or more or all researchers?
- Process:
Here, we remove the lines to focus on the author collaborations. - Image 3.2.1:
- Insight:
G. Robertson and S. Card: We see that G. Robertson and S. Card are two of three co-authors of "Cone Trees: Animated 3D Visualizations of Hierarchical Information." This is one of the three most important external papers. In the Infovis Symposia, G. Robertson and S. Card do not work together.
M. Chuah and S. Roth: M. Chuah and S. Roth collaborated on two papers, highlighted in the visualization. They are the only authors of "On the Semantics of Interactive Visualization," and they are two of four authors of "SDM: Malleable Information Graphics." After 1996, they each wrote other papers, but no longer collaborated on the same papers.
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