Synopsis
		sfmig2 < inp.rsf vel=vel.rsf > out.rsf gather=gather.rsf offset=offset.rsf adj=y normalize=y nh= antialias=1.0 apt=nx angle=90.0 half=y verb=y rho=1.-1./nt dh= h0=

The axes in the input are {time,midpoint,offset}
The axes in the offset are {1,midpoint,offset}
The axes in the output are {time,midpoint}
The axes in the "image gather" are {time,midpoint,offset}

February 2016 program of the month:
http://ahay.org/blog/2016/02/18/program-of-the-month-sfmig2/

Parameters
		bool adj=y [y/n] adjoint flag (y for migration, n for modeling)   float angle=90.0 angle aperture   float antialias=1.0 antialiasing   int apt=nx integral aperture   float dh= offset sampling (for modeling)   string gather= auxiliary output file name   float h0= first offset (for modeling)   bool half=y [y/n] if y, the third axis is half-offset instead of full offset   int nh= number of offsets (for modeling)   bool normalize=y [y/n] normalize for the fold   string offset= auxiliary input file name   float rho=1.-1./nt Leaky integration constant   file vel= auxiliary input file name   bool verb=y [y/n] verbosity flag

Used In
		DATA          freeusp/land   M8R          data/freeusp   RSF          school/data school2017/seismic school2020/seismic   SEP          aal/gulf   TCCS          nmodeblend/bei svscan/beicmps varipick/newviking wetm/beivel