i have ocean currents data (going towards). conversion can use?
270-(atan2(zonal,meridional)(180/pi)) or 270-(atan2(meridional,zonal)(180/)) or entirely different?
i have gone through [this link][1] , [eol][2] website. still have no idea.
using unit circle , arctan function tried do, first quadrant zonal component(x) towards east-west positive , meridioanl component(y) north-south positive used arctan(x,y) find direction.
then 2nd quadrant 90+arctan(x,y) ???
3rd quadrant 180+arctan(x,y) ??
4th quadrant 270+arctan(x,y) ??
please correct me if wrong...
not sure asking, function atan2
gives correct quadrant, no special tricks must done adding or substracting angles result.
if write help atan2
see expects 2 parameters: y
, x
(in order) , returns angle in radians
range [-pi,+pi]
eg.
rad2deg(atan2(1,1))
gives 45 result
rad2deg(atan2(-1,1))
gives -45 result
rad2deg(atan2(1,-1))
gives 135 result
rad2deg(atan2(-1,-1))
gives -135 result
edit: if want positive angles, do:
angle = atan2(y, x); if (angle < 0) angle = angle + 2*pi; end
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