SCATTERPLOTS AND MOUSE INTERACTION.

Here we show two things at once through a series of short movies. The two things are:

  1. Basic mouse interaction common to all Quail graphics.
  2. The basic scatterplot.
We use illustrate the first on the second.

Mouse input

In Quail, we take the pointing device to be a three button mouse. On those systems where this is not the case (e.g. Macintosh) the three buttons are faked via combinations of mouse button and keyboard operations (e.g. the default middle button on a Mac is the Option Key + Mouse ).

In addition to the three mouse buttons (left, middle, and right), there are two modifier keys, namely Shift and Control (ctrl).

The Scatterplot Example

The first thing we demonstrate is the classic scatterplot as it appears in Quail. The data here is a set of 100 observations recorded by A.A. Michelson in 1879 on 15 variates. This was the first published work by Michelson in a life-long quest to determine the speed of light in vacuo. It is one of the datasets which is provided in Quail.

In this first clip, we show the scatterplot pretty much as it would have appeared from the Scatterplot selection from the plots menu (e.g. see the plots menu tidbit). Here we illustrate the left button interaction with the scatterplot. Principally, left button simply selects (and highlights) the graphical component which appears under the mouse cursor. Multiple selection is achieved by Shift + Left button selection. In a scatterplot, multiple points can be selected by sweeping out an area of the point cloud.

  • Clip 1 (~63K): Selecting the components of a scatterplot.

As the first clip demonstrated, a scatterplot is a data structure which contains many components. This is typical of nearly all graphics in Quail. For a scatterplot, the components are: Title, Left View (the vertical axis), Left label (the label outside the left axis), Bottom View (the horizontal axis), Bottom Label (the label below the bottom axis), and the Interior View (the point-cloud). The values of the text strings, axis labels, data ranges, etc., are determined from information found on the dataset itself. It is also possible to have scatterplots with Top views, Right views, and corresponding labels. Each component of the plot is a structure in and of itself that just happens to have been visually laid out according to the definition of a scatterplot. As its own separate object, then, each graphical component can have behaviours specialized to its object type (i.e. class). These are made available to the user through middle button selection of the graphical object (or View as its known in Quail). Middle button selection pops a menu tailored to that object. In the clips which follow, middle-button menus are illustrated for the components of the scatterplot:

Things to note:

  • Sometimes part of the menus do not appear in the movies; this is because only that part which appeared within the frame of the window was recorded.
  • Menus are hierarchical.

Technical notes

  1. Movies that are recorded here are recorded in Quicktime. If your browser doesn't have a Quicktime plugin, you might want to visit the Quicktime site.
  2. The movies may be a little choppy because there are few frames per second recorded.
  3. If things are happening too quickly, remember that you can move through the movie at whatever speed is most convenient for you.

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November 17, 1999.