KAPERTURE - generate the k domain of a line scatterer for a seismic array

kaperture [optional parameters] >stdout

Optional parameters
x0=1000 point scatterer location
z0=1000 point scatterer location
nshot=1 number of shots
sxmin=0 first shot location
szmin=0 first shot location
dsx=100 x-steps in shot location
dsz=0 z-steps in shot location
ngeo=1 number of receivers
gxmin=0 first receiver location
gzmin=0 first receiver location
dgx=100 x-steps in receiver location
dgz=0 z-steps in receiver location
fnyq=125 Nyquist frequency (Hz)
fmax=125 maximum frequency (Hz)
fmin=5 minimum frequency (Hz)
nfreq=2 number of frequencies
both=0 = 1 gives negative freqs too
nstep=60 points on Nyquist circle
c=5000 speed
outpar=/dev/tty output parameter file, contains:
xmin, xmax, ymin, ymax
and npairs (needed for psgraph or xgraph)
Notes:
nfreq=1 produces fmin
nstep=0 suppresses the Nyquist circle
and npairs
Examples:

Default case: both=0 nfreq=2

kaperture nshot=NSHOT ngeo=NGEO nstep=NSTEP |
psgraph n=NPAIRS,NSTEP mark=1,0 marksize=1,0 linewidth=0,1 |...
WHERE: NPAIRS=NSHOT*NGEO

Other cases:

both=0 nfreq=NFREQ > 2
kaperture both=0 nfreq=NFREQ nshot=NSHOT ngeo=NGEO nstep=NSTEP |
psgraph n=NPAIRS,NSTEP mark=1,0 marksize=1,0 linewidth=0,1 |...
WHERE: NPAIRS=NFREQ*NSHOT*NGEO

both=1 nfreq=NFREQ > 2
kaperture both=1 nfreq=NFREQ nshot=NSHOT ngeo=NGEO nstep=NSTEP |
psgraph n=NPAIRS,NSTEP mark=1,0 marksize=1,0 linewidth=0,1 |...
WHERE: NPAIRS=NFREQ*NSHOT*NGEO*2

When in doubt to the size of NPAIRS, redirect output of kaperture to
/dev/null the first time to get npairs=:
kaperture [optional parameters] > /dev/null