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AnswersQ8

• Is a histogram an example for a visualization that is using elision (grouping together many items that share one property (usually being in the same interval)? 

• As far as i understood it, the design choices discussed in this chapter are mainly applied when designing a visualization were the possibility of user-interaction is given (the use can more or less choose what s/he wants to see) - especially the ones that require 3D-visualization, as this type of visualization comes with the cost of occlusion which can be compensated by user interaction (f.e. if the user can move the model). What are the alternatives, when interactive visualization is not possible? Would f.e. a slideshow of different views of the model be a good idea (f.e. some that shows it in general from different angles, some that shows several detailed views,…)?  

• I heard that few people can actually 'think in 3D'. Now I don't exactly know what that means, since I have the impression that other people as well as me are usually able to do so. But if this is true, shouldn't that be considered when visualizing data in 3D?  

• How can be augmented standard widgets for filtering controls by concisely visually encoding information about the dataset?  

• Why simple averaging is very likely to have the effect of avoiding the elimination of the interesting signals in the dataset in the process of summarization?  

• What is a fine-grained structure in the lower-dimensional plots?  

• Are there any specific "rules" for constrained navigation, for example, how many objects to show when zooming in/out,etc? Or it depends on visualization tool and data?  

• What is, for example, the best way to project a 3D model of a human skull or pelvis to a 2D piece of paper? 

• I can see how item filtering would work with silders for range etc., but how would one go about filtering attributes with a GUI. A slider selecting a range of attributes probably won't do.  

• Is it wise to use boxplots? They seem terribly complicated, most common people will never even have heard of lower and upper quartiles.  

• Could you explain Principal Component Analysis again in the lecture? 

• Zusammenhang zwischen Navigieren und Zusammenfassen  
  Ist das das Zoomen (navigate) zwischen Ebenen, wie in Figur 11.10 (Seite 253) gezeigt, die Auflösung einer vorhergehenden Zusammenfassung (aggregate)?  

• I don´t understand what is the meaning of Figure 11.2 on page 241 in context of Filtering. What should be filtered here? Do the User has any kind control on these dataset or in is loaded in the visualizator? Is it possible to filter any attributes and what kind of information is going to be filtered with this utility?  

• Are there any kinds of 3D – Scatteplots and why is the 3D perspective not often used in the Visualization.  

• According to p.248 and the item Navigation with rotation of the “camera” I would like to know if there is any way to optimize the view because with 3d objects it is better to use rotation, to see the details, but using the rotation in 2d vie the picture is not going to be clear and detailed for the User.  

• Was genau wird in Figure 11.16 dargestellt? Trotz einer guten Einführung in das 'Slice and Cut' ist der Sprung von 3D auf XD leider nicht (oder nur schwer) nachvollziehbar.  
• Verstehe ich das richtig, dass Figur 11.6 einen Scatterplot zeigt, bei dem gleich auftretende Attribute farblich kodiert werden? Falls ja: das gegebene Beispiel erinnert aufgrund seiner Gleichmäßigkeit mit einem StackedAreaPlot zu verwechseln und erschwert das Verständnis.  

• […] Ist der SolarPlot tatsächlich ein empfehlenswertes Idiom? 

• Was sind Hierarchical parallel coordinates? Konnte die Erklärungen und das Beispiel leider absolut nicht nachvollziehen.  

• Which vis tools not support both types of navigation?  

• Does the MDS technique is still recommended to use? because a human eyes are very sensitive with a color information, it might be difficult for some people.  

• "All these vis systems seem to be designed to show large amounts of data, what is the minimal amount of data to use with these systems?" and "It looks like the biggest reason for using on of these systems seems to be number of data to shown, is that true and are there other maybe more easily readable methods to see similarities like VisDB does?" 

• The systems also seem taylored for specific uses, and for people that are familiar with the data that is shown, are there more widely used scenarios for using one of them? 

• Wie kann man sich ein ein Interface für unconstrained Navigation vorstellen? Gibt es das überhaupt?  

• In welchen Faellen sind Non deterministischen Reduktionen besser als deterministische oder umgekehrt?  

• Shouldn't aggregation be more discussed at the level of the data? Aggregation combines several items to a new one. So the visualization of a single item and the visualization of a aggregation of several items is the same, or isn't it? (f.e. in a maps, when i aggregate two regions into one new bigger one)  

• The only difference between histograms and bar charts is the missing gap and the fact, that histograms are based on aggregated data. But isn't almost every diagram somehow aggregated? Let's say monthly income (in €) displayed in a bar chart where one bin represents a whole year of income. Shouldn't that f.e. be in a histogramm?  

• Should boxplot charts be used for the broad viewer? While boxplot charts give a good impression of the data, many viewers do not understand them. So should I use them when my viewership is big with members of every social layer. I ask this, because nontheless I attended a technical high school I first heard of boxplots at university. And it is not unusual to see them in some newspapers. Which alternatives to boxplots which are easier to understand?  

• Continuous Scatterplots: The description mentions that many HW-acceleration-techniques exist to avoid explicit computation. Which exactly, and which of those are used in praxis? 

• Whats the difference between a continuous scatterplot and 2D-Histogram? 

• Is meant by embedding focus and context together (as described in 12.2) something like a overview map on a country map? Would that be a good example?  

• Isn't distortion with a fisheye lens, as shown in figure 12.5, only useful in interactive vis where the user can point directly to the field of interest in a mere of data? To be honest, I don't see much usefulness in a static fisheye lens. 

• What are the differences between magical lens, magnification fields, superimposing and fisheye lens?  

• I don't see/understand the distortion part in figure 11.4 (p. 260), it looks just like the DOITStree in figure 11.2 (p.258) 

• Why, with which properties ist FilmFinder specific example of the general dynamic queries approach? 

• "Ich mag die Einführung zu Histogrammen nicht, da sie meiner Meinung nach falsch und irreführend ist. Wenn ich mich nicht irre, ist bei einem Histogram nicht die Höhe sondern die Fläche des Balkens das ausschlaggebende Kriterium, und das wird nicht absolut nicht so präsentiert." and "Concerning histograms and bar charts (for quantitative data), as far as I know the main difference is that the spatial encoding in histograms is area-based. Also, it would be interesting to learn about aggregation criteria for histograms. (So, 'more on this point?' - yes!)" 

Critique / Additional Notes

• Principal Components Analysis(PCA): Figure 11.11 shows variance with additional synthetic dimensions, but I don't understand how should the Figure be interpreted? Maybe this is not a good example for PCA.  

• As all readings I also like this chapter, but I think that the examples way to abstract. Like the HyperSlice, I don't think that I get the idea how to use it or for which case of visualisation. 

• Das Buch selbst finde ich sehr gut geschrieben, jedoch sind manche Definitionen ziemlich verwirrend bzw. schwer nachzuvollziehen. In diesem Kapitel fand ich zum Beispiel den Teil "Hyperbolic Geometric" etwas verwirrend. Hier hat mir auch die Grafik nicht wirklich geholfen es zu verstehen. Manche Dinge sind im Text sehr einfach erklärt aber schnell wird es sehr kompliziert. Bei manchen Visualisierungstechniken kann ich mir auch kaum vorstellen, dass man diese in der Praxis oft benutzt (z.B. Grafik 12.10).  

• Ich finde, das Example: SolarPlot ist doch etwas schwer zu verstehen, vielleicht auch, weil die Art des Diagramms doch sehr ungewöhlich ist.  

• Das Example: Hierarchical Parallel Coordinates ist bei begrenzter Anzahl übersichtlich und gut zu erkennen, aber wenn es zu viele Linien werden ist es nur noch ein großes Durcheinander und man kann darin gar nichts mehr sehen.  

• Mag die einfache und nachvollziehbare Erklärung der Vase plots (Fig. 11.7b) 

• Ich komme mit den voranschreitenden Kapiteln des Buchs von Tamara Munzner immer mehr zu dem Schluss, dass allgemein erläuternde Beispiele zu kurs kommen. Oftmals werden sehr abstrakte Erklärungen mit sehr spezifischen und eher komplexen Beispielen erläutert, die dem Verständnis nicht beitragen, sondern im Gegenteil das Verständnis eher sogar behindern. 

• I still don't get it, why reducing the amount of data is a crucial strategy in designing a vis tools.  

• according to the figure 11.7 (b), vase plots uses additional spatial dimension within the glyph by altering the width of the central box according to the density, it's seems quit clear, but the shape in the graph is quit difficult to understand, especially at 11.7 (b) for (s) Skewed shape. 

• Eine Anmerkung hätte ich nocht zu "Geometric Zooming". Am Ende dieses kurzen Abschnitts schreibt sie ob sie noch zusätzliche Informationen dazuschreiben sollte oder ob sie ein Bild einfügen sollte. Ich finde zwei einfache Bilder von einem Menschen der ein Blatt Papier hält würden das ganze noch einfacher machen. Auf einem Bild hält er das Bild etwas weiter weg und auf dem anderen näher am Gesicht.  

• I wasn't happy with figure 12.3. Maybe rethink/redo figure 12.3? I think it would be good to actually have some context with what the figure shows. For example what does the value 2.5 stand for?  

• Etwas verwirrend finde ich es, dass manchmal eine Grafik zum nächsten Beispiel bzw. Unterkapitel schon im Beispiel davor eingefügt ist. (Abbildung 11.6: Es wird Item Aggregation am Beispiel von Histogrammen erläutert und im Text ist schon eine Grafik zu Scatterplots). Ich vermute dass dieses Problem an dem Entwurf liegt und gelöst wird, sobald das Buch veröffentlicht wird. 

• Figure 11.10 (p.268). Maybe a combination of a and c could be beneficial. A white background to highlight the focused element and their closest neighbors that slowly fades out towards the edges. 

• Panning is, if I am not mistaken, a rotation of the camera around a horizontal or vertical axis (and not a kind of translation as implied in 11.5).