Spin

To effectively operate a spin plot, a few terminologies have to be defined or clarified:

The slider in a Spin plot controls the speed of rotation.

The 3 line segments in a Spin plot indicate the orientation of the 3 data axes of the data coordinate system. The intersection of the 3 line segments is the centroid of the associated point cloud. Drawing of the 3 line segments can toggled on or off by invoking Show Orientation Indicators in the right-click menu over a spin plot.

You press the plus or minus button to start rotation in the positive or negative direction. A point cloud will keep rotating as long as the plus or minus button is pressed. The following keyboard accelerators can also be used to control rotation:

There are 3 ways to draw point icons in a Spin plot: as 1-pixel points, as 2-pixel-by-2-pixel rectangles, and as circles. Drawing circles is the most computing intensive and drawing 1-pixel points the least. On Linux machines, the default is always to draw circles because circles can handle overstriking better than points and rectangles and also because Linux machines can handle the computing needs of fast drawing lots of circles. Due to the inherent nature of Microsoft Windows systems, Argos will choose a point format based on the number of points [2] in a point cloud so that rotation speed is maintained at a point for viewers to recover 3D data structures visually. You can use Draw Points , Draw Circles , or Draw Rectangles in the right-click menu of a spin plot to change drawing format manually.

Note

In order to create the illusion of rotation in a 3 dimensional space on a flat screen, a Spin plot has to update its display many times per second, which means drawing operations have to be as fast as possible. As it takes more time to draw objects of different shapes and sizes, a design decision was made to make all point icons in a Spin plot of the same shape and size. An implication of this design decision is that changing the size and shape drawing styles of observations will not have any effect on point icons in a Spin plot. On the other hand, operations Draw Points , Draw Circles , and Draw Rectangles only affect point icons in a Spin plot and do not have any effect on the drawing styles of the observations those point icons represent.

Notes

[1]

Type the lower case X to invoke this keyboard accelerator. "X" is used because that is what's printed on a keyboard.

[2]

Ideally, the speed of the computer running Argos should be taken into account, too.