This "view" shows the spectra along the straight or curved line
selected in the SP profiles tool. It also controls the wavelength
range(s) used to compute the IQUV and P views in the windows
(the window numbers are selected via the SP profiles tool).

All wavelengths are shown in the IQUV spectra displayed here. Clicking
the left mouse on a spectra will display a line plot of the profiles
at the spatial position associated with the mouse location. The orientation
of the wavelength/space display is controlled by the leftmost option
button and the spatial direction can be zoomed via the option button
to its right. The "redraw slice" button will redraw the earlier
defined line if it was lost because of a re-expose of the 2-D IQUV and P
views.

The W and S text boxes on the right control the wavelength and spatial
indices used (respectively). The spatial index is used only for the profile
line drawings and only the single value is used. The wavelength index
can be more complicated. If the "V sum width" text box contains a 1 and
the "V mirror center" is 0 (or negative), then just the single value is
used for all the 5 2-D views (IQUV and P). This allows displaying the
appearance of the area at a specific wavelength as if the image were
a filtergram or spectroheliogram.

If the "V sum width" box has a value > 1, then the QUV and P views (more
on the P view below) will have a value summed over that number of wavelengths
starting at the index value in W. In addition, if the "V mirror center" is > 0,
it is taken to be a center for a "mirror" region. This is generally intended
to be a line center position so that the 2 W index ranges are on opposite
sides of the line. With such a "mirror" set defined, the QU views are sums
over both ranges while the V could be a sum or the difference of the sums
on the two sides depending the "+" or "-" option. Because V is generally of
opposite sign on opposite sides of the line, the "-" will show most of the
V signal while the "+" will show a net signal. The latter may be useful for
searching for unusual structures.

The "P style" option button controls what is computed in the 2-D P view.
Normally the "QU" option is most useful and in this case all of the Q and U
values for all the wavelength indexes (as specified by the "V sum width" and
the "V mirror center") are squared before adding and the result is the square
root of this sum. If V is included, either the sum or difference of the 2
mirror regions is also included in the sum. Usually this is used without V
since the V signal tends to dominate when included. The "QU+" option differs
in that the summation over the indices is done first and followed by a square
and a square root (effectively doing an absolute value of the sum). Again, when
V is included ("QUV+"), the "mirror" set (if specified) is either added or
subtracted from the initial index set.

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