Download ALMA Graphical User Interfaces

3.4
Spatial Tab
Figure 12: Source Visualization
The Spatial tab is used to precisely specify the observation target. This can be done by entering parameters in the Target UI component set and by interacting with a visual depiction of the target and its
vicinity (retrieving FITS images from a server). Comments about tab management and offscreen content
navigation facilities (expand/collapse buttons and scroll bars) have been made earlier in this document.
The following comments apply to the FITS visualization panel.
This panel (Figure 12) is very reminiscent of ds9’s interface (Figure 13). This is both an advantage and a
disadvantage. It is an advantage because many astronomers use ds9. Most of them will thus be familiar
with multi-scale interfaces based on a main viewport plus a magnifier plus a panner. This is a disadvantage
because this type of UI design is old and does not scale. For instance, having the magnifier as a static inset
means that it is not smoothly integrated with the visualization in the main viewport, and that it is potentially
far from the cursor (which controls the content of the magnifier, as the latter shows a magnified version of
region surrounding the cursor in the main viewport). This causes problems of divided attention [6], that can
be solved by using state-of-the-art focus+context visualization techniques such as Sigma lenses [25, 26].
Similarly, the panner could be enhanced, so that it behaves more like current overview+viewfinder widgets
[21] (see Google Maps for an example). Of course, if FITS images to be visualized in the spatial tab are
small and do not really require the use of the panner and magnifier, then the current UI layout and features
will do. But if it is anticipated that relatively large FITS images will be loaded, then S(moderate to
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