MANET

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	Missings
	Are
	Now
	Equally
	Treated

A brief summary of MANET features

MANET basics

Plots in MANET

First Interactive Implementations of

New Interactive Features

Ongoing Research includes

Odds & Ends

New interactive features

• Context Sensitive Querying

  Option-click in any part of any plot provides information specific to that display: counts, values, numbers highlighted. To indicate, that a subsequent click will pop-up an information box, the shape of the mouse changes to a pointer with an additional questionmark, while pressing the option-key.

  Examples:

  Querying in a Scatterplot	Querying in a Mosaic Plot

  The following table lists all possibilities of queries available in MANET:
  (Clicking always means option-clicking)

  Missing Value Chart	Clicking a horizontal bar of the chart shows the number of recorded and missing values in the bar and the numbers highlighted
  Barchart	Clicking a bar of a barchart shows the number of values in the bar and the numbers highlighted
  Histogram	Clicking a bar in the histogram shows the number of values in the bar and the numbers highlighted and the limits of the interval of that bar
  Boxplot	Clicking any part of the box shows the values of the median, upper and lower hinges as well as inner and outer fences
  	Clicking outside the box shows a horizontal rule, labeled with current position of the mouse, and the number of points at this position
  Scatterplot	Clicking an axis shows a horizontal respectively a vertical line together with its position in the scatterplot
  	Clicking any horizontal bar at the bottom of the scatterplot shows the number of recorded and missing values in this bar and the numbers highlighted
  	Clicking on any point in the scatterplot, shows the values (or ranges) of the two coordinates, and the number point at that position (if points overlap)
  Mosaic Plot	Clicking any bin in the plot shows a list of the variables and their values corresponding to that bin as well as the number of values falling in this bin and the numbers highlighted
  Weighted Histogram, Barchart & Mosaic Plot	The interrogation results include the percentage of the weightings in the class and the percentage highlighted

   

• Extended Querying

For scatterplots and polygon plots exists an extended querying. By holding the shift button during the querying all currently selected variables in the variables list are listed with the corresponding values.

• Cues

  MANET has a number of features which become apparent whenever the cursor changes shape as a cue that clicking or clicking and moving will alter the display.

  Plot	Cue	Functionality
  Histogram		Change the bin width of the histogram
  		Change the offset of the histogram
  		Cyclical switching between: Histogram Average shifted Histogram + Histogram Average shifted Histogram
  		Adjust scaling after a redefinition of the bin width, to fit into the window again.
  		Switch to the corresponding spinogram (width proportional to cases for each bin). to switch back.
  Barchart		Switch to the corresponding spineplot (width proportional to cases in that category). Changes to to switch back.
  		Grab (while pressing the control key) a bar to exchange or to move to an other position
  Dotplot		Cues to switch between a horizontal and a vertical layout of the dotplot.
  Scatterplot		Flip the x and y axes of the scatterplot
  Mosaic Plot		Switch to model display: Mutually independent Drag & drop model

• Redframing

  Indicates hidden information due to

  • limited screen resolution, or
  • points falling out of the plot canvas.

  Limited screen resolution

  A warning can be found in the context of highlighting. There are two special cases, when highlighting can give trouble. The first case occurs, whenever a very small bar or bin is highlighted with very few values. If the unhighlighted bar or bin is only 2 to 5 pixels of height on the screen, a proportion of less than 10% would have less than 1 pixel of height, and thus not be plotted at all. Although the user could interrogate the bar or bin by a single optionclick, finding out the right values, it is important to prevent the user from overlooking the highlighted values. This is done by a redunderlining of the bar or bin. The complementary case, where nearly all values are highlighted except for a few, not plotted, values, is handled in the same way.

  The third situation where warnings can occur, are plots where the binsize differs dramatically from the number of values that bin should represent. This is due to limited resolution of the computer screen.

  Left red line: Although 100% of the pixels of the bar are highlighted, not all of the cases are selected

  Right red line: The highlighting display is correct, but the area of the bar differs dramatically from the size it should have.

  Points falling out of the plot canvas

  An often overlooked problem arises if observations fall out of the plot area, and thus are clipped. To indicate this MANET plots an extra red frame inside the plot window.

• Selection Sequences

  Application of interactive graphics for advanced selection techniques and graphical database queries.

  Packages offering interactive statistical graphics like Data Desk, JMP or SAS-Insight, have been around for about ten years now. These packages support a selection of a subset of the data by different tools and selection modes (and, or, xor, etc.). Usually a selection is directed and hierarchical, what the above mentioned packages do not take into account. Thus changing any element inside a sequence results in a complete redefinition of all selections. Selection-Sequences store all selections in parametric form in a hierarchical object, enabling local changes of any plot in the sequence. In addition the parametric information of Selection Sequences offer an easy way to translate a selection into a database query language like SQL, as well as the handling of relational data.

  An Example:

  Imagine the following scenario: You are interested in the 2-dimensional distribution of LHead vs. LChest - the lower right scatterplot - for different years and protection systems. A natural way to do this, would be to select a year and successively intersect with a protection system. But switching to other years or protection systems would require a totally new selection, starting with the year again. To avoid this, Selection-Sequences store the whole selection path, i.e. Number of plot Selection mode Selected cases in that plot for each window, and add a small icon at the lower right of each window in the sequence. Thus the user can easily select another year, or another protection system, and watch the changing of the scatterplot, without loosing the selection information in the other plots.