FUNCTION Rad_To_Deg, rad
  return, rad * (360.0 / (2 * 3.1415926))
END

FUNCTION Deg_To_Rad, deg
  return, deg * ((2 * 3.1415926) / 360.0)
END

FUNCTION Vector_MagDir, u, v
;takes two orthogonal vectors, u and v and returns bearing from v, and magnitude

u_pos = abs(u)
v_pos = abs(v)
u_neg = u lt 0.0
v_neg = v lt 0.0

mag = sqrt( (u_pos^2) + (v_pos^2))

dir = acos ( v_pos / mag )
dir = rad_to_deg(dir)

;get the quadrant information
;true = 1, false = 0
quad = (4 * u_neg) + (2 * v_neg)
quad_add = (0.0 * (quad eq 0)) + (90.0 * (quad eq 2)) + (180.0 * (quad eq 6)) + (270.0 * (quad eq 4))

dir = dir + quad_add

out_var = fltarr(n_elements(mag[*,0]),n_elements(mag[0,*]),2)

out_var[*,*,0] = mag
out_var[*,*,1] = dir
return, reform(out_var)
END

FUNCTION Vector_MagDir2, u, v,r=r,a=a
;problem with vector_magdir when v = 0, use arctan instead

x = double(u)
y = double(v)

w = where((x NE 0) OR (y NE 0),count)
a = u*0
IF count GT 0 THEN a[w]=atan(x[w],y[w])
w = where(a LT 0,count)
IF count GT 0 THEN a[w]=a[w]+2*!dpi
r = sqrt(x^2+y^2)
a = rad_to_deg(a)
return,transpose([float(r),float(a)])
END



FUNCTION Vector_UV, mag, dir

;reverse of above function   vector_uv(vector_magdir(m)) = m
;much simpler

dirrad = deg_to_rad(dir)

u = mag * sin(dirrad)
v = mag * cos(dirrad)

if n_elements(mag) eq 1 then out_var = [u,v] else begin
  out_var = fltarr(n_elements(u[*,0]),n_elements(u[0,*]),2)
  out_var[*,*,0] = u
  out_var[*,*,1] = v
endelse

return, reform(out_var)
END

FUNCTION Anglexy,val1,val2
  magval1 = sqrt( val1[0]^2 + val1[1]^2)
  magval2 = sqrt( val2[0]^2 + val2[1]^2)
  angle = acos(((val1[0]*val2[0])  + (val1[1]*val2[1]))  / (magval1 * magval2))
  return,angle
END

PRO Rotatexy,angle,x,y,xnew,ynew
  xnew = (x * cos(angle)) + (y * (-sin(angle)))
  ynew = (x * sin(angle)) + (y * cos(angle))
END