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 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