Need formula - wind direction

[dmarkwick 261]

A while back people were very helpful in suggesting ways for me to get wind strength, which turned out to look like this:

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">_WindStrength = (SQRT((wind select 0)^2 + (wind select 1)^2));

Now, for two rather cool micro-projects, I need to know the wind direction too.

Can any maths gurus suggest a formula for getting wind direction? I suggest using wind select 0 and wind select 1 as I only need lateral direction. They will give you a positive or negative number depending on wind direction and speed, which should give you a vector from which a direction should be got, using some sort of trigonometry witchcraft I expect

[mtlgd 0]

http://community.bistudio.com/wiki/wind

I would suspect it works on the same principle as VectorDir does for players. 0,1,0 for north.....

Mtl

[mtlgd 0]

I was wrong, doesn't work out quite the same, interesting though, appears to have a slight updraft if this read vaguely the same.

[ManDay 0]

You know what cosine and sine are?

[dmarkwick 261]

Yes

[ManDay 0]

Heard of tangent as well? :P

[t_d 47]

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">_fVectorLength =

{

sqrt( ((_this select 0)^2)+((_this select 1)^2)+((_this select 2)^2) )

};

_fVectorDotProduct =

{

private["_v1","_v2"];

_v1=_this select 0;

_v2=_this select 1;

(_v1 select 0)*(_v2 select 0) + (_v1 select 1)*(_v2 select 1) + (_v1 select 2)*(_v2 select 2)

};

_fVectorAngle =

{

private["_v1","_v2","_v1l","_v2l"];

_v1=_this select 0;

_v2=_this select 1;

_v1l=_v1 call _fVectorLength;

_v2l=_v2 call _fVectorLength;

acos(([_v1,_v2] call _fVectorDotProduct)/(_v1l*_v2l))

};

_wind2D = [wind select 0, wind select 1, 0];

_angle = [_wind2D,[0,1,0]] call _fVectorAngle;

_windDir = if((_wind2D select 0) < 0)then{360 - _angle}else{_angle};

[raedor 8]

A bit easier...<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">_wind = wind;

hint ("Wind dir: " + str ((_wind select 0) atan2 (_wind select 1)))

[Master85 1]

... and with full 360° ...

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Code Sample </td></tr><tr><td id="CODE">_wind = wind;

hint str((((_wind select 0) atan2 (_wind select 1)) + 360) mod 360);

[dmarkwick 261]

Ooh thanks guys atan2 was exactly the thing

[[GLT] Legislator 66]

Hmm very interesting. This script only shows the wind strength, right? Is it possible to influence the wind strength depending on meteological data? I had the idea of influencing the behaviour of air vehicles during a huge storm and connecting it with mission.