Display Window Information Area

The Display window starts with the default display of the data set as specified by the AIPS View window Options Default:(Show) toggles. For a raster display this will be a linear mapping to the display palette of the data values between the selected data values of interest (defined by the Data range slider in the AIPS View window). The name of this window (which is displayed at the top) is the filename with the type of cut (e.g., RA-DEC) appended. Immediately following is the scale factor of the display, such that 300% $\times$ 300% means there are 3 $\times$ 3 screen pixels for each data pixel.

The default is to have additional information about the data set show above the image in this window, as described in the following section.

Slice Information

Present only for 3D data sets. This shows what kind of slice you are looking at. The initial default is VELO (velocity), so you would see the total number of planes in the Z (velocity) axis and which of these is displayed. The world coordinate (such as the velocity value) of this plane is listed. To display a different Z-plane value, one of the arrow buttons may be clicked to change the velocity channel which is displayed or you may move the mouse pointer into the area between the arrows, delete the number displayed, type in a new number, and press the <RETURN> key. If you want to constrain the display range of the data set (which may be used for an animation or movie through only some planes of the data set), move the mouse pointer into the area where the beginning or end plane number is displayed, delete the number displayed, type in a new number, and press the <RETURN> key.

**Figure 2.14:** **Slice Information** Subpanel
$\begin{figure}\begin{center} \epsfig{file=Aipsview.dir/displaySliceInfo.eps, height=0.23in}\end{center}\end{figure}$

Value

The next field down the window is the Value button, turned on by default. The label of the button will be the units for the data or Value if the data set did not supply a string. When this is on (click the button with the left mouse button to toggle), the pixel coordinates, world coordinates, and data value are displayed when the mouse pointer is in the Display window and the left button is clicked. Note that the display of the world coordinates is formatted by default (e.g. RA is displayed in hours, minutes, seconds) but the coordinates can be displayed as the raw numbers by activating the Raw Position toggle from the Misc submenu of the Options menu of the Display window, see Section 2.3.4. When the value button is on, there is a box drawn around the selected pixel in the image window to indicate the current position. It is only drawn when the mouse button is released unless the scaling is 600% or more in which case the box will follow the cursor (there is no point in drawing the box with smaller scalings since it can't be seen under the cursor). The value information is continually updated as the mouse pointer roams the Display window with the left button held down. A blanked pixel will cause the word Blanked to appear rather than an intensity number.

**Figure 2.15:** **Value** Subpanel
$\begin{figure}\begin{center} \epsfig{file=Aipsview.dir/displayValue.eps, height=0.41in}\end{center}\end{figure}$

Region

Turned off by default (unless this default has been overridden by selecting the Region toggle from the Defaults:(Show) submenu from the Options menu of the AIPS View window). For an individual display window, the region can be displayed by selecting Region from the Show submenu of the Options menu of the Display window (see Section 2.3.4). This area shows the region which has been selected, which by default is the entire region. By pushing the Region button, one activates region selection. Pressing the left mouse button at a pixel in the Display window, dragging to another pixel, and releasing the mouse button defines a new region, which is displayed as a rectangle in the display window. The pixel and world values of the subregion will be displayed in this area of the Display window. By pushing the Display Region button, one can get a new Display window showing only the selected region (n.b., to clone a window, turn on region selection then immediately choose Display Region - the default region is the entire window).

**Figure 2.16:** **Region** Subpanel
$\begin{figure}\begin{center} \epsfig{file=Aipsview.dir/displayRegion.eps, height=0.94in}\end{center}\end{figure}$

Profile

Turned off by default (unless this default has been overridden with an AIPS View window Options toggle); see Options menu (see Section 2.3.4). For 3D data sets, there is a profile area of the window. By clicking on the Profile button, you get a profile plot when the mouse pointer is in the Display window and the left button is clicked. The zero line is also plotted. A vertical line marks the plane currently being displayed; this line will move through the profile if a movie (see Section 3.1.1) is being run. In combination with the slice information at the top of the Display window, this line can be used to read precise coordinates. Additionally, clicking the left mouse button in the profile window will display the plane closest to that velocity in the raster display.

**Figure 2.17:** **Profile** Subpanel for default (*left*) and previewed (*right*) displays.
$\begin{figure}\begin{center} \epsfig{file=Aipsview.dir/displayProfile.eps, height=3.4in}\end{center}\end{figure}$

The profile (as well as all ``included'' profiles whose world coordinates overlap) is continually updated as the mouse pointer roams the Display window with the left button held down. If a 3D data set (with velocity as the third axis) is displayed, the profile is the usual spectral line (data value versus velocity) plot. If an RA-VELO slice is being displayed, the profile display would be a data value versus DEC profile. By default, the intensity range displayed is the entire range present in the data; this may be changed by use of the data range slider at the bottom of the AIPS View window (see Section 2.2.3). If some spectral channels are blanked, the blanked channels appear as gaps in the displayed spectrum.

If the Lock button is pressed, the profile generated in this window will be locked to the current position in this window and all windows which include it. One way to use the lock feature is to compare profiles from different positions in the same data set. Since Aipsview doesn't directly support this, it will be necessary to create a subregion (see Section 2.4.3) and turn on overlaid (included) profiles.

If the Print button in the profile area is clicked, a PostScript file of the displayed profile will be created in the current directory. You may override the printing defaults; see Appendix A.1 for customization information. The name of the PostScript file will be the window name (in the title bar of the Display window) with the pixel position and .profile.ps appended (e.g., smallcube.RA-DEC.1-015-006.profile.ps). The appearance of the output profile can be controlled by opening the Profile Setup window (i.e., select the Profile item from the Edit menu of the Display Window, see Section 2.3.2). Note that the characteristics such as line color, style, and width of included profiles are controlled by their respective Profile Setup window. Thus, if you wish to double the line width of the frame, the displayed profile, and all included profiles, you would need to change the line width in the Profile Setup window of this profile and all included profiles.

Next to the Print button there is a Preview toggle; selecting this toggle changes the default profile window (see left-hand panel of Fig. 2.17) to a larger version which shows what the hardcopy output will be given the current choices in the Profile Setup window (see right-hand panel of Fig. 2.17). There is nothing preventing you from keeping the previewed profile displayed. However, selecting the preview window is enlarges the total window, which may not be desirable. Also, it takes significantly more time to redraw the previewed profile than the default profile when moving the cursor around an image. Note, that the ability to click in the default profile window to select the display of the nearest channel, as well as the vertical line showing the displayed channel, is not available in the previewed profile.

Clicking on Dump button will write the X and Y values of the profile to an ASCII file (n.b., there are three lines of header information at the top of the dumped file). The name of the dump file will be the window name (in the title bar of the Display window) with the pixel position and .profile.dump appended (e.g., smallcube.RA-DEC.1-015-006.profile.dump). Note that you must have write permission in the directory containing the image to write any hardcopy (PostScript or ASCII files).

Raster Display

The aipsview defaults have been set up to show an overview of the image on a 256 $\times$ 256 pixel display. A smaller image is expanded to 256 $\times$ 256 by pixel replication. If the image to be displayed is larger than 256 $\times$ 256, the displayed image would be subsampled (e.g., every second pixel of a 512 $\times$ 512 image would be displayed). The scaling can be changed from the default by using the Scale menu of the Display window, see Section 2.3.3.

**Figure 2.18:** **Raster Display** Subpanel
$\begin{figure}\begin{center} \epsfig{file=Aipsview.dir/raster.eps, height=1.9in}\end{center}\end{figure}$