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- can smoothly adjust buoy size and location |
- can smoothly adjust buoy size and location |
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We draw the link targets as buoys around the focus. |
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Layout requirements: |
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- buoys should not be placed over the focus |
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- buoys should be placed close to their anchors |
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- buoys anchored closer to the focus should be larger |
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- the layout should animate continuously when the focus moves |
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Furthermore, |
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It is important to maintain orientation locally (i.e., left/right |
It is important to maintain orientation locally (i.e., left/right |
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direction of links, etc.) but the space need not be globally |
direction of links, etc.) but the space need not be globally |
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euclidian. This matches the way the brain understands space |
euclidian. This matches the way the brain understands space |
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as globally distorted, segmented, locally Euclidian views. |
as globally distorted, segmented, locally Euclidian views. |
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Some refs (should search for more/better): |
Some refs (should search for more/better): |
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http://acad88.sahs.uth.tmc.edu/research/publications/iccs2001spatial.pdf |
http://acad88.sahs.uth.tmc.edu/research/publications/iccs2001spatial.pdf |
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[#wang01mindsviews]_ |
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http://citeseer.nj.nec.com/hunt99orientation.html |
http://citeseer.nj.nec.com/hunt99orientation.html |
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Because of this, each link has a specific left-right orientation ... |
That is, going in one direction should result in arriving from |
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the opposite direction. |
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Geometry: |
Because of this, each link has a specific left-right orientation |
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so that a right-end buoy is drawn on the right side of the view |
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and a left-end buoy on the left side. |
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- buoys on a circle |
More than two opposing directions could also be used, but |
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- matches fisheye shape |
- it is not required for maintaining the sense of direction |
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- other reasons? |
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- why not simply straight lines on left/right sides? |
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- projected from a constant point (on left/right) through the |
- it would limit the layout of a large number of buoys |
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anchor to right/left side of the circle |
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- projections are easy to track for humans |
- there is usually no meaningful global 2D layout of a network |
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of nodes; in our application, the structure has simply |
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directed links, visualized as the left-right direction. |
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- final positions may be adjusted to prevent too much overlap |
The horizontal orientation is more natural than, e.g., vertial, because |
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the visual field is wider than it is tall |
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(exemplified by the usual screen aspect ratios of 4:3 and 16:9) |
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leaving more space at the left and right sides than on the top and bottom. |
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XXX: left and right hand??? |
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- how does this interact with the perception of the projection? |
We choose the geometry as follows: |
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- buoys are placed on a circle centered at the focus and diameter |
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little less than the screen height |
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- buoys far from the focus are drawn at the anchor instead |
- buoys equally close to the focus, matching the fisheye focus shape |
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- provides more space for the buoys than, e.g., a straight line |
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(a circle arc is longer) |
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- buoys anchored outside the buoy-circle are drawn near the anchor instead, |
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to prevent awkward view-cutting long lines and to yield more space |
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for the layout of buoys anchored closer to the focus |
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- the position on the circle is obtained by projecting from a constant |
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point (on left/right) through the anchor to right/left side of the circle |
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- buoys placed close to the anchor |
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- such line projections are easy to track for humans, |
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because it is analogous to 3d perspective |
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- final positions may need be adjusted to prevent too much overlap |
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- how does this interact with the perception of the projection? |
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- buoy scale |
- buoy scale is relative to the anchor's distance from the circle |
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The above design produces good results and is very simple if not |
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the simplest way to meet the layout requirements. |
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- buoys closer to the focus should be larger |
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- scale is relative to the anchor's distance from the circle |
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Break lines |
Break lines |
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