Graphics Reference
In-Depth Information
a model link. A similar situation might arise with color maps. Whether these link-
ages of color constitute a meaningful information exchange depends on the context.
At least using an identical color scheme reduces the effect of misinterpretation due
to color effects. Linking axis information typically comes down to the fact that all
linked displays use the same axis parameters. Also for the axis information it can
be said that in most instances the axis parameters are identical to the correspond-
ing scale parameters. For histograms, for example, the limits of the axes are typically
depending on the scale specified in the model. Differences between scales and axes
usually yield an ine
cient usage of the available plot space because part of the plot
remains deliberately unused. his can be intended if, for example, observations that
areexpectedtofallinasimilarrangecovercompletelydifferentportionsoftheobser-
vation space.Iftheaxesareadjustedtomatchexactly thescales, onewouldnotnotice
thisfeatureimmediately.Ifthesameaxesareused,thedifferentrangeoftheobser-
vations becomes clearly visible. A similar situation can also occur with choropleth
maps and their corresponding color scheme. Linking type information is usually an
essential ingredient for proper comparisons between various plots. he prototypes
of incorrect visual representations that can be found in many topics (e.g., Wainer,
; Monmonier,
; Tute,
) are all based on adjusting the axis parameters
too closely to the corresponding scale parameters and then interpreting the visual
differences in the plots independently of the scales.
Linking Frames
8.2.4
he frame level is the coarsest level of a data display and basically determines the
generalshapeandsizeofaplotwindow.Linkingthesizeofframesisnotonlyrelevant
for a screen-space-saving layout of displays, but it is also one of the prerequisites
for a correct comparison of graphical displays, as has been already seen in Fig.
.
.
Using different frame sizes distracts the analyst and can lead to wrong conclusions.
Linking of other attributes, such as background color, printing black on white or
whiteonblack,isnotdirectlyimportant forcorrectinterpretations andcomparisons.
However, a common framework to set and change these parameters is convenient,
especially for creating different scenarios of data analysis.
Visualization Techniques for Linked Views
8.3
he linking paradigm advocates the sharing of information between displays. his
can happen whenever a new display is created by making use of the information
that is available in the current displays. A second instance for information sharing is
presentin interactive environments whenever the usermakes changes toaplot while
investigating andexploring the data. Whilethe firstcase istypically easily realized by
creating anadditional plotwindow,thesecond caseintroduces thequestion ofwhere
the information goes and howthe information can bebest represented.Roberts etal.
