General
The DEVise (Data Exploration and Visualization) JavaScreen is a Java
applet that allows users to interactively explore complex data sets.
The JavaScreen applet connects to a DEVise server, which renders most
images the user sees. This allows large data sets to be visualized
without transmitting the full data set to the client applet.
Note that a full explanation of DEVise is beyond the scope of this
help document. This document will focus on the areas useful to the
average user of the DEVise JavaScreen.
Views
The view is the fundamental component of DEVise. A view is an
area of the screen within which symbols are displayed, with each symbol
corresponding to a record in the underlying data. One key property of
a view is the axis ranges (which are in effect even if axes are not
displayed in the view). Data outside the current axis ranges is not
displayed. (Note that three-dimensional views are somewhat different
in this respect.)
One of the most important features of views is that, in most cases,
you can change the axis ranges by dragging with the mouse or by
other actions. (See the "toolbar" and "keyboard shortcuts" sections
below for specific information on how this is done.) Some views have
their axis ranges "locked", to prevent changes that would render
the visualization less usable. In some visualizations, several views
have their axis ranges "linked", so that zooming in or out in one
view will also zoom correspondingly in other views.
DEVise Cursors
The DEVise Cursor is a rectangular "box" within a view. The
box can be moved (and in many cases, resized) by dragging
it with the mouse. When you do this, "behind the scenes" connections
will change another part of the visualization. In some cases, a DEVise
cursor is used to select a region that is magnified in another view
(this is probably the most obvious case). However, there are other uses
of DEVise cursors, such as selecting which of a number of data sets
to display.
Most DEVise visualizations are designed to be explored mainly by
moving and resizing the DEVise cursors.
Toolbar
The Toolbar (located at the left edge of the JavaScreen) allows you
to select from a number of different modes. These modes change the
behavior of the JavaScreen as described below. In general, in order to
perform a given action you have to select the appropriate toolbar
mode, and then click or drag in the view that is to be affected.
When you enter a given toolbar mode, the mouse cursor changes to
reflect the current mode.
Note that some views may not allow all toolbar actions. In such cases,
the mouse cursor will change to a no-op cursor. Also, at this time,
the toolbar only has an effect on two-dimensional views.
-
Drill down (show data records): in this toolbar mode, if you
click on a data symbol, the location of the click (in data units) and the
data associated with the symbol will be displayed. If multiple data
symbols overlap or are very close together, the drill-down dialog will
show the data corresponding to all of the symbols. If you click in an
area in which there is no symbol, only the location of the click will be
displayed.
-
Show help for selected view: in this toolbar mode, if you
click anywhere in a view, the help message for that view (if any) will
be shown.
-
Select cursor/zoom in XY/3D rotate: this is the "normal"
toolbar mode. In this mode, you can drag or resize a DEVise cursor
(if the mouse cursor is on a DEVise cursor). If you are not on a cursor
in a two-dimensional view, dragging with the mouse will zoom in on both
the X and Y axes (unless modified by keyboard shortcuts, see below).
In a three-dimensional view, dragging with the mouse will rotate the
structure (unless modified by keyboard shortcuts, see below).
Also, a single-click in a view with a cursor will move the cursor to
the mouse location. If there are multiple cursors in the view, only
one will be moved.
-
Expand DEVise cursor to fill view: in this toolbar mode, if
you click anywhere in a view containing a DEVise cursor, the DEVise
cursor in the view will be expanded (or contracted) to the dimensions of
view axes. If there are multiple cursors in the view, only one will
be resized.
-
Increase symbol size: for some symbol types, the size can
be varied. In this toolbar mode, clicking in a view with such symbols
will increase the symbol size.
-
Decrease symbol size: for some symbol types, the size can
be varied. In this toolbar mode, clicking in a view with such symbols
will decrease the symbol size. Note that the symbols cannot be made
smaller than the "default" size, so the symbols will only be reduced
in size if they have already been increased from the default.
-
Home (show all data): in this toolbar mode, clicking in a
view will set the view's axis ranges to the "home" setting. In most
cases, this means that the view will be expanded (or contracted) to
exactly the ranges required to show all data in the view. In some
cases, there is a pre-defined home setting different than this default.
Note that if the view is already at the "home" setting, performing this
operation again will have no effect.
-
Toggle axis ranges: in this toolbar mode, clicking in a view
will toggle back and forth between the last two sets of axis ranges.
-
Zoom in XY: in this toolbar mode, dragging with the mouse
zooms in on both the X and Y axes. Single-clicking zooms in on
both axes by a factor of two.
-
Zoom in X: in this toolbar mode, dragging with the mouse
zooms in on the X axis only. Single-clicking zooms in on the X axis
by a factor of two.
-
Zoom out XY: in this toolbar mode, dragging with the mouse
zooms out on both the X and Y axes. Single-clicking zooms out on
both axes by a factor of two.
-
Zoom out X: in this toolbar mode, dragging with the mouse
zooms out on the X axis only. Single-clicking zooms out on the X
axis by a factor of two.