Tan-1 in coords calculations

[malu05]

Ok what i need is to find the angle between 2 coords in a coordination system, like needed on a map.

So when i am at $Posnow and want to go to $posend i must from north (0deg) turn clockwice $y deg and then just walk forward.

example:

This is my current code

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#include <Math.au3>
;Input i give the app
$posendX = 558
$posendY = 608
$posnowX = 590
$posnowY = 587

;prepare for Tan finding the distance from X-Ynow to X-Yend 
if _Max ( $posendX, $posnowX ) = $posendX Then
$a = $posendX - $posnowX
    msgbox (1,$a,$a)
Else
$a = $posnowX - $posendX
    msgbox (1,$a,$a)
EndIf
if _Max ( $posendY, $posnowY ) = $posendY Then
$b = $posendY - $posnowY
    msgbox (1,$b,$B)
Else
$b = $posnowY - $posendY
    msgbox (1,$b,$B)
EndIf
;Tan -1
$intfortan = $a / $b
$pi = 4 * ATan(1)
$radToDeg = 180 / $pi
$y = ATan($intfortan) * $radToDeg 
;Converts from 90deg system to 360deg system
if $posendX <= $posnowX Then
$x1 = 1
Else
$x1 = 0
EndIf
if $posendY >= $posnowY Then
$x2 = 1
Else
$x2 = 0
EndIf
Select
    Case $x1 = 0 and $x2 = 0
        ;nothing
    Case $x1 = 0 and $x2 = 1
        $y = $y + 90
    Case $x1 = 1 and $x2 = 1
        $y = $y + 180
    case $x1 = 1 and $x2 = 0
        $y = $y + 270
EndSelect
;result
msgbox(1,(Floor($y)),(Floor($y) & " is final deg" ))

This is complex and does eat alot of system recourses compared to a maybe smaller code.

So anyone got some ideas of how to do this easier or shorter?

Edited November 2, 2006 by malu05

[malu05]

ok... code is wrong.. sec.. ill just fix it!

[Paulie]

ok... code is wrong.. sec.. ill just fix it!

look at the law of sines, since you know one angle will always be 90', and you can use SolidSnake's '_Distance' UDF (Search for _Distance in S&S) to find all three sides, Sin = Opposite/Hypotenuse

[malu05]

look at the law of sines, since you know one angle will always be 90', and you can use SolidSnake's '_Distance' UDF (Search for _Distance in S&S) to find all three sides, Sin = Opposite/Hypotenuse

nono, the calc was fine, it was just the way the > and < was turning.

But anyone got an idea of how to do this more easily?

[malu05]

A good example of what im trying to do is here;

http://www.itc.fa.dk/software/ies-math/tri.../sixtrigfn.html

dont mind about the danish text there but if you pull the red dot, the "Vinkel" gives the result in degrees.

My math is just crap, so i wonder if someone can help me out?