\cancel mode verify

! convert speed and direction to vector components.
! Then call stack_stick.jnl to draw stack plot

!  GO water_vector_stack spd dir lower_y upper_y

! Arguments are 
! $1  speed 
! $2  direction
! $3 lower limit on Y axes for all plots
! $4 upper limit on Y axes for all plots

! Example 
!   yes? set data 44029a2007.nc
!   yes? set region/t=1-mar-2007:15-apr-2007/k=1:10
!   yes? go water_vector_stack.jnl water_spd water_dir -40 40

 can mode logo


! Define constants for converting degrees to radians

let pi = atan(1)*4
let deg2rad = pi/180

! Variables must be on the same grid: Regrid water_dir to the grid of water_spd

let dirr = $2[g=$1]

! If there are units on the water speed variable use the same units for the vector components

define symbol vector_units = "`$1,return=units`"

! Define variables for uu and vv, vector components

IF `($vector_units) EQ " "` THEN
  let/title="Zonal Current"  uu = ABS(($1))* cos(deg2rad* dirr)
  let/title="Meridional Current" vv = ABS(($1))* sin(deg2rad* dirr)
ELSE
  let/units=($vector_units)/title="Zonal Current "  uu = ABS(($1))* cos(deg2rad* dirr)
  let/units=($vector_units)/title="Meridional Current " vv = ABS(($1))* sin(deg2rad* dirr)
ENDIF

! call stack plot script (optional arguments are the min and max vertical limits
! on the right-hand y axes.)

go stack_stick uu vv $3 $4
set mode/last verify