Large Data Sets
From the LinkWinds Reference Manual
The DataObject represents both the data and the metadata on the screen. It exists in two states, the short form and expanded. These states are toggled by pressing the "more" button which is always present. In the short form only the name of the data set is displayed, along with the "more" and linking buttons. In the expanded form, additional information about the size, location and metadata of the data set is displayed. Subsetting and palette manipulation options are also available.
The slider controls which slice of data is
displayed in applications such as Image, Plane, and Histogram.
Continuously updated tracking is possible. The slice may be along any of
the three orthogonal view axes, as selected by a button.
The 3-Axis Slider also controls which slice
of data is displayed, and provides for tracking. Three sliders exist,
one for each view axis, so a slice in any direction may be changed
without the need for clicking a button first.
The RGBSlider is used to control the
levels of any application that uses 3 slices of data. This includes
Plane, Polar and
Globe. RGBSlider is used to select three
parallel slices out of a single dataset. Triangular arrows are used to
step incrementally through the slices.
The 3-Axis Rotator rotates three
dimensional applications such as Plane and Globe. Three sliders exist,
for rotation about each of the three orthogonal axes. The rotations may
be continuously updated by means of a button.
The 2-Axis Rotator also rotates three
dimensional applications, with possible continuous updating. However,
only one slider is present, which moves in a two dimensional area. Thus,
any possible rotation may be selected by moving only one slider.
The Pan-Zoom Slider controls three
dimensional applications, providing two functions much like in a movie
camera. The panning is accomplished by a slider which moves in a two
dimensional area, and adjusts the view from which the application is
seen. The zoom slider moves in only one dimension, and controls the
distance from which the application is viewed.
The Combine Slider has six individual
sliders. Three control the slices of data used by applications, for
example in making composite RGB images or performing mathematical
manipulations on the slices. The other three sliders provide offsets to
the data values in the slices, and are useful with the mathematical
functions provided by the Combine tool.
The LightTool enables the positioning of a
light for the 3-dimensional applications. It also allows for adjustment
of the light position, as well as the characteristics of the light, and
the photometric properties of the objects being illuminated.
Contour calculates an arbitrary number of
contour lines, which may then be rendered on any of the applications
which display slices of data. The contours may be on a slice along any
of the three orthogonal view axes, and may be arbitrarily colored. A
histogram of the slice is displayed as a guide in selecting contour
levels. The contour points may be saved to a file.
The Animator provides time-based animations
of any application by subdividing control settings and governing smooth
interpolations between the settings. Any number of intermediate
positions or key frames may be set with the control applications. Each
position has an associated time, input by a clock on the Animator. The
animation is played back, and recorded by making screen dumps if so
desired, with a variety of user selected frame rates. These include
rates for film and video, as well as a "screen" mode in which frames are
rendered as quickly as possible according to the computer's
capabilities. The recorded frames may be replayed with a specially
ColorFilter is a tool which allows the
user to modify the current color palette quickly. ColorFilter ramps colors
just as the ColorTool, and likewise,
modifies the database palette. Any tools that use the database-defined
colors are affected.
The Frame Animator also makes
animations, however they are based on the number of frames rather than time.
Start and end positions are set for the controls, and the number of frames
desired set by a slider. The application being controlled is then
rendered by interpolating between these positions according to the
number of frames selected. The renderings may be saved with a "record"
option for subsequent replay with a specially provided tool.
The Color Tool provides interactive palette
manipulation of data sets during a LinkWinds session. Individual data
values may be specially marked, or a range of data may be ramped in
color between two values. A variety of palettes, including those
defined by the user, may be substituted for the original one.
The Combine tool allows different slices of
data, from either the same or different data sets, to be combined into
images using various mathematical functions. Currently, up to three
slices of data may be combined with the options listed in the pull-down
menu. In addition, a calculator is available to input arbitrary
functions of both slices and constants. An embedded histogram may be
used for interactive renormalization of the computed data. The three
slice images may also be independently displayed.
The Calculator tool performs much like a
standard calculator, but with the added capability of performing mathematical
operations on slices of data. Calculator is available on Combine and may be
called up only from a button on that application. Operations can be
performed on slices as well as constants and on combinations of slices and
constants within the Combine application from which it came.
The Compare tool compares the functional
behavior of each point in a data set with a reference point, and
displays the resulting image, the color indicating the degree of
similarity with the reference point. Several functions are available for
this comparison, including least squares.
Data Subset allows the user to
interactively save portions of the displayed data. The portions are
defined using the bounding boxes of Image, Combine, or Compare and the
sliders of LinePlot. The saved data set is given a name based on the
original data set and the size of the saved area. The name is printed to
the window in which LinkWinds is executing. The data are saved in HDF
format, and the metadata includes the size.
The LinePlot application plots the values
along a straight line going completely through a data set parallel to
any of the three axes. For comparisons, values from both tracking and
frozen crosshairs may be plotted, as well as averages over boxed
regions. In addition, because all levels are shown, LinePlot also
conveniently acts as a slider. Red, green, and blue slides may be used
to select up to three different slices, and define the A, B and C slices
Histogram displays the distribution of
values in each of the 256 data channels for up to three slices of data.
By using the two sliders available for each slice, interactive filtering
and color stretching may be done to create composite RGB true or false
color images and to enhance feature detection on single slices. Yellow
lines indicate the maximum and minimum data values. The gain of the
histograms may be adjusted to enable the viewing of bins with very low
Image displays a single slice of data from
any of the three orthogonal axes, or a composite RGB image taken from
three slices. A Color Bar at the bottom shows the current location of
the crosshair, with the numerical value written on the second line of
the top pad. The lower pad gives information about the most recent
option selected. The window automatically resizes, with scroll bars
appearing when needed. Crosshair, bounding box, and line controls are
embedded to drive other applications.
The PointInterp application renders an
image based on an irregular and/or sparse data set. This preliminary version
has some of the functionality of Plane. Absent
are relief (height), RGB and multiple data set options. The name of the data
set used is given at the upper left of the window. The rendered image may
be rotated, panned, zoomed and lit. The application window may be resized with
with the size of the rendered plane adjusting accordingly.
The Plane application renders an image in
perspective relief, with an accompanying height field. The image may be
either a single slice or a three-slice RGB composite. One or two data
sets may be loaded; their names are displayed at the upper left of the
window. If there is just one data set, then its first slice will also
act as the height field. With two data sets, the first set determines
the image while the second provides the height values. The gain of the
height is interactively adjusted by a dial. The rendered image is three
dimensional, and may be rotated, panned and zoomed. The application
window may be resized, with the size of the rendered plane adjusting
accordingly. A subset of the full image can be displayed under the
bounding-box controls of other applications.
Polar renders a slice on one of various
polar projections. Its functionality is very similar to that of Globe,
The Globe application renders a slice on a
globe, with a possible accompanying height field. The image may be
either a single slice or a three slice RGB composite. One or two data
sets may be loaded; their names are given at the upper left of the
window. If there is just one data set, then its first slice will also
act as the height field. The gain of the height is interactively
adjusted by a dial. With two data sets, the first set determines the
image while the second acts as the height field. The rendered image is
three dimensional, and may be rotated, panned and zoomed. The
application window may be resized, with the size of the rendered globe
Isoview builds up to eight isovalue
surfaces inside a three-dimensional data set. Which contour value is
used is chosen by a slider, for a single surface, and the Contour tool
for multiple surfaces. The plots can be rendered in either planar,
polar or spherical projections, with or without lighting.
OrthoView displays a psuedo-volume
rendering of all the points in a three dimensional data set which lie
between two values. The limiting values are selected using the Histogram.
The window of OrthoView is resizable, with the plot rescaled accordingly.
VolumeView displays a volumetric rendering
of the data set with transparency at a point dependent upon its data
value. The user can then view the overall structure throughout a data
Opacity allows the user to set the
transparency of the pixel values which are displayed in applications which
render with transparency. Currently this is only VolumeView, and Opacity may
only be called from a button on that application.
VectorView is a prototype of a
generalized vector field exploration tool. Currently, it only handles
scalar fields as input, then takes the gradient of those fields for analysis.
Any application with bounding boxes (e.g.Image)
can apply its bounding box to VectorView. VectorView has three display
options: it can show either a set of arrows in the direction of the field at
various points (the so-called "hedgehog plot"), it can display integral curves
of the vector field and draw them, or it can display small batons oriented in
the direction of the field at various points.
Profile displays the data values along a
line drawn on a slice of data. The slice may be from any view axis of
Image, or from the Combine or Compare tools. The line is drawn with a
pencil shaped cursor called from the menu of the drawing application,
which must be linked into Profile. Data base, slice and endpoint
information are all given. The left side of Profile corresponds to the
initial point of the line. The Profile window stretches in either
direction, with the plot rescaling accordingly.
The 2D Scatter Plot tool plots points from
two data sets. At every location in a slice, the data value of one set
is plotted against the data value of the other, giving information about
the correlation of these two data sets. If the two data sets are not of
equal size, by default the dimensions of the smaller are used. A
bounding box may be used to control the area scattered. The points are
color coded for location on the slice. A variety of statistical
information is available, and may be saved to a text file.
The 3D Scatter Plot tool plots and displays
points from three data sets. At every location in a slice, the data
values of the sets are plotted against each other, giving information
about their correlation. If the data sets are not equally sized, by
default the dimensions of the smallest are used. A bounding box may be
used to control the area scattered. The points are color coded for
location on the slice. The plot may be rotated about any axis for
TrackPixel gives numerical values for the
data displayed in the Image, Combine, or Compare applications. The upper
pad shows the location of the crosshair and the data value at that
point. The first four lines are in physical units, the last four give
the byte value of the data and the pixel location in the window. The
lower pad gives statistical information from the bounding box. These are
the coordinates of the box, the mean and standard deviation of the data
inside the box (or outside, if the box is exclusive), the minimum and
maximum data values in the bounded region, and the number of points in
ValueView displays the values of a portion
of a slice in ASCII text. As many values as fit in the ValueView window are
shown; the window may be resized to change the number of values shown.
Sliders allow the user to choose which portion of the slice to view.
Information from a Combine or Compare slice is viewable as well, by linking in the
The Draw application is used to draw simple
pictures in and around LinkWinds windows. It is intended for annotation
of LinkWinds objects and images for publication, presentation or other
interchange. It can also be used to construct special purpose overlays
for the data.
FileFinder allows the user to add
additional data files into LinkWinds, add additional draw files into the
Draw tool, and update the list of paths in which LinkWinds will search
for files. Any directory may be entered by navigating up and down the
SnapShot is a hard-copy device which allows
the user to save portions of a LinkWinds screen for subsequent printing,
or ingestion into Draw for additional preparation. The areas that may
be selected and saved are the individual rendered components inside a
LinkWinds application, an entire window of a LinkWinds application, or
the whole screen.
PointSample is an application for creating
databases. It samples a function many times to create a regularly-gridded
data object. The function is supplied by you outside of LinkWinds.
It creates inputs to the outside program, builds a LinkWinds database and
imports it to LinkWinds.
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