;data[*,*,0] : B strength
;data[*,*,1] : B inclination
;data[*,*,2] : B azimuth (azm)
;index       : index



theta=asin(sp_index[ii].xcen/960.0)
phi=asin(sp_index[ii].ycen/960.0)

bx=data[*,*,0]*sin(data[*,*,1]*!pi/180.)*cos(azm*!pi/180.)
by=data[*,*,0]*sin(data[*,*,1]*!pi/180.)*sin(azm*!pi/180.)
bz=data[*,*,0]*cos(data[*,*,1]*!pi/180.)

tmp_bx=bx*cos(theta)-bz*sin(theta)
tmp_bz=bx*sin(theta)+bz*cos(theta)

new_bx=tmp_bx
new_by=by*cos(phi)-tmp_bz*sin(phi)
new_bz=by*sin(phi)+tmp_bz*cos(phi)