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For general comments on plot navigation, see Appendix A.4.2.1.
Additional configuration options are available in the Navigation
tab of the Axes control.
Navigation in three dimensions with a two-dimensional screen and mouse
is a bit of a challenge.  However, the actions listed below should make it
fairly straightforward to navigate around points in 3d space to zoom in
on the regions that you are interested in.
The actions are quite like for the Cube Window,
but all zooming is isotropic.
- 
 Left drag Left drag
- 
Rotate.
    Rotates the view cube about its center.
    
- 
 Wheel Wheel
- 
Zoom.
    Spinning the mouse wheel forwards/backwards zooms the space in the
    view cube in/out around the cube center.  The mouse position does not
    affect it.
    
- 
 Right drag (CTRL-drag) Right drag (CTRL-drag)
- 
Zoom.
    Zooming up-and-right/down-and-left does just the same as spinning the
    mouse wheel forwards/backwards.
    
- 
 Center drag (SHIFT-drag) Center drag (SHIFT-drag)
- 
2d pan.
    Dragging with the center button pans the 3d space in the two dimensions
    best alighned with the plane of the screen.
    There is no movement in the third (mostly perpendicular to the screen)
    direction.
    
- 
 Left click Left click
- 
Select.
    If there are plotted points near the cursor it will identify one,
    plot a marker on it, and
    activate it.
    
    In 3d, it's not obvious which is the nearest point to a 2d cursor,
    since a screen position represents a line not a point.
    To break the degeneracy, the point used is the one nearest the 
    center of mass of plotted points along the line of sight represented
    by the cursor position.  The upshot of this is that if you click on
    an isolated point, you'll pick that point, and if you click on a 
    dense cluster, you'll get a point near the center (of mass) of that
    cluster.
     
- 
 Right click (CTRL-click) Right click (CTRL-click)
- 
Re-center.
    Right-clicking identifies a position in a similar way to the
    left-click Select action, and then translates the plot so that point
    is at the center of the view cube.  This means that clicking on a
    cluster will put that cluster in the center of the cube.
    If you click on an empty region, a position half way between front
    and back of the cube at that X/Y position will be used.
    
You can also manually fix the plot bounds using the Range
tab of the Axes control.
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TOPCAT - Tool for OPerations on Catalogues And Tables
Starlink User Note253
TOPCAT web page:
         http://www.starlink.ac.uk/topcat/
Author email:
         m.b.taylor@bristol.ac.uk
Mailing list:
         topcat-user@jiscmail.ac.uk