Visualization Part II Data Explorer

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Visualization - Part IIData Explorer

• Karen G. Haines
• Brian Oetiker

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Data Explorer

• Selecting Data Components
• Coloring (Autocolor, Color)
• Exporting Images
• Times series data (importing, exporting)
• Adding captions
• Exporting time series images

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Selecting and Collecting Data

• Required when altering specific data components
• The Select module is used to extract a data
  component
• The Collect module is used to group or regroup
  the data values or images
• Also can use the Arrange module to put images
  in order once data/images are collected

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Previous Plotting Example

• Values were displayed, but colors of the line
  plots were the same
• Need a legend to define the results viewed
• a legend differs from axis
• Results were not saved to an output file

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Previous Plot ProgramExercise 5
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Previous General Array File C/Windows/Desktop/DX
_Class/Examples/2D_Plots/Ex4.general
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Previous Plot Results
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Exercise 6Selecting Data Components

• Reopen VP from previous lecture
• C/Windows/Desktop/DX_Class/Examples/2D_Plots/Ex5.
  net
• Create a Select module for each data component
  and connect output of the Import to each module
• Open the Select module dialog and enter the
  appropriate component under the which input
• which Professors or Students
• Case sensitive
• Component names should correspond to names in GAF
  file (Ex4.general)

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Exercise 6Coloring and Labeling Data Components

• Create a Color module for each data component
  and connect output of the Select to each module
• Open the Color module dialog enter a different
  color for each data component
• Create an Options module for each data
  component and connect output of the Color to
  each module
• Set the appropriate options in the Options
  module
• attribute1 label
• value1 professors or students

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Exercise 6Regrouping Data Components

• Create a Collect module and connect the output
  of both Options modules to the input of
  Collect
• Connect the output of the Collect module to the
  input of the Plot module
• Execute the program

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New Plotting Program
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Colored Plot with Labels
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Rendering an Image

• Output of Image module is a renderable object,
  but it is not a rendered image
• Can save the image by hand using Save Image
  under the File menu options in the Image
  window
• To create an image, need to first render the
  image using the Display or Render modules
• Both modules require camera component inputs

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Rendering

• Uses a specified camera to create an image of an
  object
• Rendering properties of an object (shading) can
  be changed with the Options of Shade modules
• Render always invokes the software renderer
• By default, creates 96-bit images
• Creates 24-bit images if the DXPIXELTYPE
  environment variable is set to DXByte
• setenv DXPIXELTYPE DXByte

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Display

• Displays an image or renders and object an
  displays an image
• If a camera is not specified, the system assumes
  the input object is an image to be displayed
• Must use the Image module rather than Display
  if you want an inter-active display environment
• With Display, DX automatically selects the
  hardware-appropriate rendering format

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Exercise 6Rendering an Image

• Create a Render module
• Connect the first output of Image (the image)
  to the first input of the Render module
• Connect the second output of Image (the camera)
  to the second input of the Render module

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Exercise 6Rendering an Image
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Writing an Image to an Output File

• Once an image is rendered, it can be written to
  disk in various formats using the WriteImage
  module
• A variety of standard image file formats are
  supplied
• Gif, Tiff, RGB, YUV, eps-color, eps-greyscale
• Need to have permission to the directory where
  the image is to be saved

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Exercise 6Writing an Image

• Create a WriteImage module
• Connect the output of Render to the input of
  WriteImage
• Invoke the WriteImage dialog box
• Select the gif output file format
• Enter the name of the output file with no
  extension
• C/Windows/Desktop/DX_Class/Examples/2D_Plots/plot

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Final 2D Plot Program

• Execute the program to make sure it is working
  correctly
• Save the resulting program
• C/Windows/Desktop/DX_Class/Examples/2D_Plots/Ex6

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Final 2D Plot Program
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Importing and Displayingan Image

• To import an image in a format known to DX, use
  the ReadImage
• To view an image that has already been rendered,
  use the Display module

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Exercise 7Displaying Images

• Invoke a new VP
• Create a ReadImage and a Display module
• Connect ReadImage to Display
• Think data flow
• Input the name of the image file created in the
  previous exercise
• C/Windows/Desktop/DX_Class/Examples/2D_Plots/plot
  .gif
• Execute the program
• Save program
• C/Windows/Desktop/DX_Class/Examples/2D_Plots/Disp
  lay

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Exercise 7Displaying Images
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Visualizing 2D Time Series Data

• Best method for representing time series data is
  animation
• For 2D time series data, DX can be used to create
  a series of output images that can be used to
  create an animation
• A variety of output standard image formats are
  provided

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Importing an Image Series

• Example data file information
• 60 10 x10 2D block data values stored
  sequentially
• data type of values is float
• data depicts 2D population values over time
• file
• C/Windows/Desktop/DX_Class/Examples/timesSeries/i
  mages.foxP

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Exercise 8Importing 2D Time Series Data

• Invoke the Data Prompter
• Select Grid or Scattered file
• Regular grid
• variables 1
• make sure single time step is deselected
• Data organization is block
• Data file
• C/Windows/Desktop/DX_Class/Examples/timeSeries/im
  ages.foxP

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Exercise 8Describing 2D Time Series

• Grid 10 x 10
• Format ASCII
• Order Column
• Series
• n 60 start 1 delta 1
• Field
• name foxes
• type float
• Save file
• C/Windows/Desktop/DX_Class/Examples/timeSeries/fo
  xP

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Visualizing 2D Time Series Data

• Need to process each time slice of data
  consecutively to create a series of output images
• Requires a means for accessing each slice of data
  one at a time
• Data representation must remain consistent for
  the entire data set

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Exercise 9Displaying 2D Data

• Invoke the VPE (new program)
• Add the modules
• Import ? RubberSheet ? Image
• Input the file previously created
• C/Windows/Desktop/DX_Class/Examples/timeSeries/fo
  xP.general
• Execute the program
• Investigate different views

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Exercise 9Displaying 2D Data
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Problems with Current Visual Program

• Sequenced data not viewable as a time series
• Colors do not optimally represent the data
• Output images are not created

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Adding the Sequencer

• Loading in the data all at once limits DX
• Need to import the images one by one in
  sequential order
• Use the Sequencer module to control the
  processing of sequential images
• Sequencer basically generates a sequence of
  integers and has attributes to control the count

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Exercise 9Add the Sequencer

• Create a Sequencer module
• Expand the dialog for the Import module, apply
  the change, then close dialog
• Start, End, Delta
• Connect the Sequencer output to the fourth
  (start), fifth (end), and sixth (delta) tabs of
  the Import module
• Execute the sequencer

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Exercise 9Add the Sequencer

• Change the execution mode to sequencer
• Access the series control attributes by clicking
  on the ellipsoids on the Sequencer control
  panel
• Change the maximum number of images to 59
• Execute the program

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Exercise 9Add the Sequencer
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Adding Color

• Current visual program does not best represent
  the data - need to have color control
• Need a means of color control
• Modules for coloring include AutoColor and
  Color

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Autocolor Module

• Automatically colors a data field by mapping hues
  to data
• Adds colors to the color component
• Adds a color map attribute to output object
• Color map component is created
• color look up table with 256 entries

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Exercise 9Automatic Coloring

• Create an Autocolor module
• Connect the output of Rubbersheet to the input
  of AutoColor
• Connect the output of AutoColor to the input of
  Image
• Execute the program

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Exercise 9Automatic Coloring
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Autocolor with Time Series Data

• AutoColor module uses minimum and maximum data
  values to create a color map
• typically red maximum blue minimum
• Problem with using AutoColor module with time
  series data is that the color mapping changes
  each with image

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Constant Color Control

• To retain the color representation for the entire
  series
• Control requires the use of two modules
• Colormap and Color
• Colormap is a means of creating a specific map
  of colors
• Color colors the data

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Exercise 9Color and Colormap

• Delete AutoColor module
• Create a Color and a Colormap module
• Connect the output of Rubbersheet to the first
  input tab of Color and the output of Colormap
  to the second input tab of Color
• Connect the output of Color to the input of
  Image
• Set the maximum value of the colormap to 10.0
• Execute the program

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Exercise 9Color and Colormap
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Captions

• Caption module is used to display a caption on
  a screen
• Can change the color of the caption using the
  Color module
• When using Image or Display changing the size
  of the image will not affect the size of the
  caption
• need to use ScaleScreen to change caption size

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Exercise 9Adding Captions

• Create a Caption module
• Invoke and expand the Caption dialog to set the
  following parameters
• string Total Student Population
• position 0.5 0.95
• height 48
• font roman_s

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Exercise 9Adding Captions

• Create a Collect module
• Connect the output of Color and the output of
  Caption to the inputs of Collect
• Connect the output of Collect to the imput of
  Image
• Execute the program

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Exercise 9Adding Captions
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Creating a Series of Output Images

• Before an image can be written, it must be
  rendered
• When working with time series output, want any
  output time slice to correspond to its respective
  input time slice
• Need a means of formatting the outfile names as
  the function of the sequence

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Rendering an Image Revisited

• Two modules to render an image
• Display
• Render
• Both need camera coordinates
• Camera coordinates can be directly sourced from
  image

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Exercise 9Rendering an Image

• Create a Render module
• Connect the first output of Image (the image)
  to the first input of the Render module
• Connect the second output of Image (the camera)
  to the second input of the Render module
• DO NOT EXECUTE THE PROGRAM

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Exercise 9Rendering an Image
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Creating a Series of Filenames

• Sequencer generates a stream of integers
• Format module formats a string
• To create a list of file names that are in
  synchronization with the Sequencer, the output
  of the sequencer is used as input into a
  Format module to generate a string much like
  the C programming language

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Exercise 9Creating a Series of File Names

• Create a Format module
• Connect the output of Sequencer to the second
  input of Format (the value)
• Invoke the Format dialog and set the template
• C/Windows/Desktop/DX_Class/Examples/timeSeries/im
  age.d.gif

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Exercise 9Creating a Series of File Names
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Creating a Series of Output Files

• At this point we have
• a series of rendered images
• a series of file names
• To generate sequential output image, all that
  needs to be done is to create a WriteImage
  module and connect the images and filenames to
  module

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Exercise 9Creating a Series of Output Files

• Create a WriteImage module
• Connect the output of Render to the first input
  tab of WriteImage
• Connect the output of Format to the second
  input tab of WriteImage
• Execute the program
• Save the program
• C/Windows/Desktop/DX_Class/Examples/timeSeries/Ex
  9

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Exercise 9Resulting Program
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