From Visualization Sp06
Assignment 1: Visualization Critique
Reshaping Nature with the View Camera
Source: Photographing Nature p210
The above visualization is intended for photographers who intend to take photos of nature - just as the title of the text suggests.
The author is trying to illustrate how nature photos tend to have a certain distortion which gives an unneeded perception sometimes. Specifically speaking, he is referring to the distortion created by positioning the camera view at an angle thus creating a perception that the trees meet up at some spot not in the view of the photograph.
He rectifies the correct way of taking the photograph by displaying a sample on the right. The core idea is to place the view straight so as to avoid the unwanted distortion.
This visualization is a little hard to deconstruct given the constructs of the material we have covered.
2 examples are provided to demonstrate the point of the visualization which I think is excellent because without the examples it might have been tough to understand the idea.
The orientation of the camera in the bottom images is used in a subtle manner to demonstrate the difference. Fortunately, the spacing of the images is not too far and hence it is possible to view both the orientations in the span of half a second. Thus, it is the positioning of the images in close proximity that helps its cause.
The core element being used in this visualization is the position of all the objects (N) - by objects I include the sample images, the caption and graphics to display the view angle. The very simple fact that there is no quantity or order mentioned places it in the Nominal category. One could argue that the angle at which the camera is tilted could be a quantity but the purpose of the image is to demonstrate images with distorted perceptions and ones without it. Hence it is Nominal.
Firstly, a critism in my belief would be that the designer could have used color in this example, specially since the distorted perspective would be even more clearer had color been used as one could use fading of color to demonstrate the pointer in a quicker manner. Black and white also does the job just fine but that is what I would do. Now to argue the other side, the lack of color allows the image from not becoming to gaudy. The bottom graphics are best of displayed in black and white and by making the above images color, it would steal attention from the most important element of the visualization. Thus, the lack of hue I must specify, allows for equal distribution of attention.
The top images are positioned close enough to notice the differences quickly. The bottom graphics have more spacing but it is rightly deserved because the difference is a little more subtle with the orientation of the camera.
The captions allow you to quickly notice the discrepencies in the photographs and allow a smooth transition into the educational aspect of the graphic. It is fine positioning of elements in this visualization that struck me as well done. Furthermore, the images were well chosen and the flow of the visualization goes well from examples to text to education that even a novice can understand the point in a matter of a minute.
Range of ground acceleration
Source: Modern Global Seismology
The visualization is attempting to display the acceleration measurement of the earth using specific seismological instruments. The image in particular is comparing the IRIS GSN System and WWSSN instrumentation.
In addition to the comparison, it is showing the readings based on a range of the size of the earthquakes, varying between 5.0 and 9.5.
The target audience for such an image is seismology students. The chapter is expected to be the first introduction of seismometry to the students.
The visualization uses a combination of image and data models.
Amongst the first things that stand out is the shape of the graphs(Q). It is attempting to display a range of values for ground motion over time. The range of the shape creates a perception of area
It even uses an object which is another form of shape (stars in this case) to display something I just cannot seem to understand, hence this graphic is under the bad visualization section. It is suppose to display the ground acceleration of a specific magnitude, highlighted on the side of the trend but it raises more questions.
The x-axis is logarithmic time, highlighted by the x-tics and x-values, which is common in seismology (Q).
The y-axis is also an ordered range with a clearly fixed 0 hence it is a quantitative data model.
There is also an implicit usage of position if one pays attention to the Earth Tides and arrows for Dynamic Range. The image was created to give a relative view of Earth tides to earth acceleration.
This graph has several things going wrong for itself. Taking this seismology course, I have trouble deciphering the reason for displaying some of the elements on this graph.
Firstly, the graph does not have a legend to specify what the stars stand for. Furthermore, the repeated use of the star for a different magnitude, in the lack of any color aid, just causes more confusion. The way the designer resolved the issue is by cluttering the graph with more text and adding the labels alongside the stars.
The label for the y-axis is placed vertically causing the reader to tilt their heads and possibly giving them a different perspective of the shape of the graph. In this matter, I think it is a little harsh on the designer because to label the axis correctly and conserve space, it is needed to place the text at that orientation. (Yes, I know I am refuting my own point but it is to cover all bases).
Fortunately, the one thing the graph does do correctly is get the models right i.e. compare the correct type of data. Visual presentation - another story.
The creator could have made excellent use of color to demonstrate the point quickly and cleanly. This could have lead to the usage of a legend and hence avoided the extra text in the graph.
The vertical bars just add to the clutter.
The positioning of the WWSSN shapes inside the IRIS GSN System shape is a well though idea as it very quickly highlights the extent of the IRIS system over the WWSSN system.
Finally, the caption mentions about the ground acceleration in a different unit compared to what is displayed on the graph. After having spent over 30 minutes analysing the graph, I finally understand it - not to mention that is a little long!