Introduction to Prism

Why does my GUI look different?

The CIAO GUIs use the default GTK theme specified on each user's machine to determine how the GUI is displayed (e.g. gray background with selected items in blue). Your GUI may look different than the one shown in screenshots in this thread, but the functionality is the same.

The help file on guis has instructions on how to change the default theme.

Tabbed File Viewing

It is possible to open several files in tabbed frames in a single instance of prism.

To open a file in a new tab, use the "File → Open New Tab" menu to select the file to open. There is also a "File → Recent New Tab" option which opens a recently-viewed file in a new tab. Figure 3 shows two files loaded in separate tabs.

Figure 3: Opening files in tabs

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Figure 3: Opening files in tabs

Neither of the files has write permission, indicated by the red X icon at the left edge of each tab.

Viewing ASCII Data

Prism is able to display simple ASCII files through the Data Model ASCII kernel. The files are opened in the same manner as FITS tables:

unix% prism input.txt

All the features of prism can be used with ASCII data, e.g. table editing, plotting.

Plotting Data

Any two or three columns of data may be plotted within. This example will use the "Interactive" method of plotting.

Open the aspect solution file, pcadf084271087N002_asol1.fits, either in a new tab or within the existing one.

unix% prism pcadf084271087N002_asol1.fits &

1. Highlight the desired two columns for plotting by clicking on the column name; the first column selected will be plotted along the x-axis, the second along the y-axis. In this example, ra and dec are plotted.

2. Click the "Plot" button to open the Plot Settings window. Alternately, you could choose the "Plot → Quick Plot" option.

3. Set the plot options. For this plot, the line style is set to "shortdash" and the symbol style is set to "none". The line color is changed to red (#f00f00); uncheck the "Default" box and then click the square to select the line color. Figure 5 shows the set options.

   In CIAO 4.4, it is also straightforward to set these options in the ChIPS GUI after creating the plot.

   Figure 5: Setting plot options

   

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   Figure 5: Setting plot options

   The default setting is to clear any plots in the current ChIPS window before plotting the data.

4. Click "Apply" to create the plot and leave the options window open.

The plot of telescope RA vs. Dec is shown in Figure 6.

Figure 6: Plot of RA vs Dec

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Figure 6: Plot of RA vs Dec

Plotting RA vs Dec reveals the telescope dither pattern (a Lissajous curve).

The plot settings window can be used to change or add to the plot options. To make a plot of time vs RA, choose "time" from the "Curve X" menu and "ra" from the "Curve Y" menu. The menus are populated with the columns from the data file.

After changing the line style to "solid" and setting the color to blue, click "Apply". The plot is updated, as shown in Figure 7.

Figure 7: Plot of time va RA

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Figure 7: Plot of time va RA

The plot of time vs RA shows one direction of the dither pattern over time.

Choose "OK" to close the plotting window when you are done.

Creating Images

Any two columns of data may be binned into an image and then displayed.

Open the event file, acisf01843N002_evt2.fits, either in a new tab or within the existing one.

1. Highlight the desired two columns for binning by left-clicking on them. In this example, the x and y (sky) columns will be used.

2. Select the "Image → Quick Image" option.

ds9 is launched with the image loaded (Figure 8).

Figure 8: An image in (x,y) coordinates

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Figure 8: An image in (x,y) coordinates

The image was centered in the window by middle-clicking in ds9.

The default binning factor is 8. To select a different binning, use the "Image → Interactive Image" option and change the value in the image settings window.

Make a Histogram

A histogram is made from a single column. This example will use the "Quick" method of making a histogram.

The event file, acisf01843N002_evt2.fits, should still be loaded from the image example. If it is not, open it in prism again.

1. Highlight the desired column for the histogram by clicking on the column name. The energy column is used in this example.

2. Select the "Histogram → Quick Histogram" option.

A ChIPS window containing the histogram (Figure 9) is opened.

Figure 9: Histogram of energy (eV)

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Figure 9: Histogram of energy (eV)

This histogram shows the distribution of counts as a function of energy.

The default histogram binning is 50. To select a different binning, change the selected column, or customize the display, use the "Histogram → Interactive Histogram" option.

This histogram is used as the starting point for the Customizing Plots section. Leave the window open for the next step in this thread.

Using the ChIPS GUI

The ChIPS GUI is new in CIAO 4.4. It allows you to modify an existing visualization, e.g. change the symbol style and line color of a curve, adjust the limits and scaling of an axis, or resize a plot.

Right-click on the ChIPS window and select the Show GUI option to launch the GUI. In the Info panel, click to select the histogram object (“Histogram hist1” in Figure 10).

Figure 10: Customizing a histogram with the ChIPS GUI

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Figure 10: Customizing a histogram with the ChIPS GUI

Selecting an object in the Info panel brings up the properties that can be edited.

Using the color selector in the "Histogram Properties", set the Line Color to red and uncheck the Droplines box. Then select the "Symbols" tab and change the histogram symbol to "cross". The plotting window is updated automatically after each action is completed.

The modified histogram is shown in Figure 11.

Figure 11: Histogram modified from the ChIPS GUI

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Figure 11: Histogram modified from the ChIPS GUI

The appearance of the histogram has been modified from the ChIPS GUI.

When you are done modifying the histogram, "Print" can be used to send the plot to the printer or to save it in a file.

For more information on the GUI:

• Introduction to the ChIPS GUI thread
• the ahelp chipsgui page
• the Help/Reference Manual menu from the GUI

Connecting to the ChIPS Server

When a plot or histogram is created, an instance of the CIAO plotting program ChIPS is started to display the results. After connecting to this ChIPS session, any ChIPS commands can be used to modify the plot. For instance, changing the axes to log scale - an option which isn't available from the plot settings window.

Start ChIPS in any window in which CIAO is running:

unix% chips
-----------------------------------------
Welcome to ChIPS: CXC's Plotting Package
-----------------------------------------
CIAO 4.4 ChIPS version 1 Friday, December 2, 2011

chips>

The list_servers() command shows the ids of the available ChIPS servers; in most cases there will only be one server running - the one created by prism.

chips> list_servers()
         ['ChipsServer_16803_1']

There is only one server running currently, so it must be the one used to make the histogram. When the histogram was created, a message in the status box also indicated that this was the server used, e.g.:

Mon 25-Jan 16:55:03 Connected to chips server 'ChipsServer_16803_1'

The connect() command connects the ChIPS session to that server. Since there is only one server running, we have the option of omitting the server id:

chips> connect()

OR

chips> connect("ChipsServer_16803_1")

Now the ChIPS session is aware of all the information relating to the histogram:

chips> info()

Window [win1]
  Frame [frm1]
    Plot [plot1]   (0.15,0.15)  .. (0.90,0.90)
      Border bottom [bx1]  top [bx2]  left [by1]  right [by2]
      X Axis [ax1]
      Y Axis [ay1]
      Histogram [hist1]

For instance, add symbols and set the line color to red:

chips> set_histogram("symbol.style=cross line.color=red")

The modified histogram is shown in Figure 12.

Figure 12: Histogram modified from a ChIPS session

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Figure 12: Histogram modified from a ChIPS session

The appearance of the histogram has been modified from the ChIPS session.

Since the plotting window is now attached to both the prism GUI and the ChIPS session, you can close prism and continue to modify and add to the plot from the xterm.

The ChIPS website has more examples of modifying plots.

Cell Editing

To change the value of a cell, click on it and enter the new value. Collapsed vector or array columns must be expanded before they can be edited.

Figure 13: Selecting a table entry for editing

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Figure 13: Selecting a table entry for editing

On the first click, the cell contents are selected. Type to replace the information with a new value.

While in editing mode, <TAB>, <SHIFT>-<TAB>, and the arrow keys may be used to move through the rows and columns to select different cells.

When a new value is supplied, data type and range validation (if appropriate) are performed. If the change is invalid - e.g. a string provided for an integer column - the cell background is set to red (Figure 14). The status area also displays a message to indicate if a value had changed or a reason if an edited value did not change. In Figure 14, the error reads

Thu 08-Jan 14:06:24 Unable to convert d to datatype long    (previous value=4)

The user must manually correct the error in the value.

Figure 14: Entering an incorrect cell value

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Figure 14: Entering an incorrect cell value

In addition to the visual cue, the status window reports that there was a problem with the supplied value.

Append a Column or Row

1. To append a new column to the open table extension, select the "Append Column" from the "Edit" menu in the toolbar and a window (Figure 15) will appear. There are fields for the column name, units, and description fields, as well as a dropdown menu to set the data type. If "Array" or "Vector" is selected, an additional field specifies the number of array elements or vector dimensions.

   Figure 15: Append Column to Table window

   

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   Figure 15: Append Column to Table window

   A value of "2" will be used to seed the new column.

   Click "OK" to add the column (Figure 16).

   Figure 16: Viewing the new column

   

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   Figure 16: Viewing the new column

   The new column is added to the end of the column listing.

2. To append a new row to the open table extension, select the "Append Row" from the "Edit" menu in the toolbar and a window (Figure 17) will appear. The new row can be seeded with the values of an existing row - chosen by the selector box or slider - or it can be created empty.

   Figure 17: Append Row to Table window

   

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   Figure 17: Append Row to Table window

   The new row will be created with all zero values.

   Click "OK" to add the row (Figure 18).

   Figure 18: Viewing the new row

   

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   Figure 18: Viewing the new row

   The new row is added as the last row in the file.

Editing Header Keywords

In the Header Keywords section of prism there are two buttons: "Add" and "Delete". Select "Add" and the Add Header Keyword window (Figure 19) opens. There are 4 text fields - keyword name, value, units, and comment string - as well as a dropdown menu to set the type.

Figure 19: Add Header Keyword window

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Figure 19: Add Header Keyword window

The new keyword will be a string type called NEWKEY with the value "A new keyword".

Click "OK" to add the keyword (Figure 20).

Figure 20: Viewing the new keyword

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Figure 20: Viewing the new keyword

The new keyword (NEWKEY) is added as the last keyword before the processing history section of the header.