SUK1K2FILTER - symmetric box-like K-domain filter defined by the cartesian product of two sin^2-tapered polygonal filters defined in k1 and k2

suk1k2filter <infile >outfile [optional parameters]

Optional parameters:
k1=val1,val2,... array of K1 filter wavenumbers
k2=val1,val2,... array of K2 filter wavenumbers
amps1=a1,a2,... array of K1 filter amplitudes
amps2=a1,a2,... array of K2 filter amplitudes
d1=tr.d1 or 1.0 sampling interval in first (fast) dimension
d2=tr.d1 or 1.0 sampling interval in second (slow) dimension
quad=0 =0 all four quandrants
=1 (quadrants 1 and 4)
=2 (quadrants 2 and 3)

Defaults:
k1=.10*(nyq1),.15*(nyq1),.45*(nyq1),.50*(nyq1)
k2=.10*(nyq2),.15*(nyq2),.45*(nyq2),.50*(nyq2)
amps1=0.,1.,...,1.,0. trapezoid-like bandpass filter
amps2=0.,1.,...,1.,0. trapezoid-like bandpass filter

The nyquist wavenumbers, nyq1 and nyq2, are computed internally.

verbose=0 verbose = 1 echoes information

tmpdir= if non-empty, use the value as a directory path
prefix for storing temporary files; else if the
the CWP_TMPDIR environment variable is set use
its value for the path; else use tmpfile()

Notes:
The filter is assumed to be symmetric, to yield real output

Because the data are assumed to be purely spatial (i.e. non-seismic),
the data are assumed to have trace id (30), corresponding to (z,x) data

The relation: w = 2 pi F is well known for frequency, but there
doesn't seem to be a commonly used letter corresponding to F for the
spatial conjugate transform variables. We use K1 and K2 for this.
More specifically we assume a phase:
-i(k1 x1 + k2 x2) = -2 pi i(K1 x1 + K2 x2).
and K1, K2 define our respective wavenumbers.


Credits:
CWP: John Stockwell, November 1995.

Trace header fields accessed: ns, d1, d2