Synopsis
		sftan2dang < in.rsf > out.rsf na=360 da=0.5 oa=0.0 nr=2*nsx dr=0.5*dsx or=osx

Parameters
		float da=0.5   float dr=0.5*dsx line summation sampling   int na=360   int nr=2*nsx line summation samples   float oa=0.0   float or=osx line summation origin