Editing Revisiting SEP tour with Madagascar and SCons (section)

===Windowing and plotting===
Our next task is to window and plot a significant portion of the data. Add the
following line to the <tt>SConstruct</tt> file:
<syntaxhighlight lang="python">
Flow('windowed','Txx.HH','window n2=10 min1=0.4 max1=0.8')
</syntaxhighlight>

The window command selects the first ten traces and the time window between
0.4 and 0.8 seconds.
We will plot the windowed data with three different plotting programs.
<syntaxhighlight lang="python">
plotpar = '''
transp=y poly=y yreverse=y pclip=100 nc=100 allpos=n
'''

for plot in ('wiggle','contour','grey'):
    Result(plot,'windowed',plot + plotpar)
</syntaxhighlight>

For convenience, plotting parameters are put in a string called
<tt>plotpar</tt>. A Python string can be enclosed in single, double,
or triple quotes. Triple quotes allow the string to span multiple
lines. In this case, we use triple quotes for convenience. Next, we
loop (using Python's <tt>for</tt> construct) through three different
programs (<tt>wiggle</tt>, <tt>contour</tt>, and <tt>grey</tt>). For
each program, the command portion of <tt>Result</tt> is formed by
concatenating two strings with Python's addition operator.
Try running <tt>scons -Q wiggle.view</tt>. You should see something like the
following output in your terminal:
<pre>
bash&#36; scons -Q wiggle.view
< Txx.HH /path/to/RSF/bin/sfwindow n2=10 n1=200 f1=200 > windowed.rsf
< windowed.rsf /path/to/RSF/bin/sfwiggle transp=y poly=y yreverse=y 
pclip=100 nc=200 > Fig/wiggle.vpl
/path/to/RSF/bin/sfpen Fig/wiggle.vpl
</pre>
and a figure similar to Figure~(fig:wiggle) appearing on your
screen. The <tt>-Q</tt> switch tells SCons to run in a quiet mode,
suppressing verbose comments. We will use it from now on to save
space. You can dismiss the figure by using the "q" key on the
keyboard or by hitting the "quit" button.
Run <tt>scons -Q view</tt>, and you should see simply
<pre>
bash&#36; scons -Q view
/path/to/RSF/bin/sfpen Fig/wiggle.vpl
</pre>
Since the <tt>wiggle.vpl</tt> figure is up to date, SCons does not rebuild
it. After quitting the figure, SCons will resume processing with
<pre>
< windowed.rsf /path/to/RSF/bin/sfcontour transp=y poly=y yreverse=y 
pclip=100 nc=200 > Fig/contour.vpl
/path/to/RSF/bin/sfpen Fig/contour.vpl
</pre>
and a figure appearing on your screen. Quitting the figure, produces
<pre>
< windowed.rsf /path/to/RSF/bin/sfgrey transp=y poly=y yreverse=y 
pclip=100 nc=200 > Fig/grey.vpl
/path/to/RSF/bin/sfpen Fig/grey.vpl
</pre>
and the next figure.
[[Image:wiggle.png|frame|center|To see this figure on your screen, run <tt>scons~wiggle.view</tt>]] 
[[Image:contour.png|frame|center|To see this figure on your screen, run <tt>scons~contour.view</tt>]]
[[Image:grey.png|frame|center|To see this figure on your screen, run <tt>scons~grey.view</tt>]]