ATAN2 03-07-2020 11:38 AM

[Greg_Deckler]

DAX doesn't have an ATAN2 function so I created one.

ATAN2 = 
    VAR __x = MAX('Table'[X])
    VAR __y = MAX('Table'[Y])
    VAR __atan2 = 
        SWITCH(
            TRUE(),
            __x > 0, ATAN(__y/__x),
            __x < 0 && __y >= 0, ATAN(__y/__x) + PI(),
            __x < 0 && __y < 0, ATAN(__y/__x) - PI(),
            __x = 0 && __y > 0, PI()/2,
            __x = 0 && __y < 0, PI()/2 * (0-1),
            BLANK()
        )
RETURN
    __atan2

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[Anonymous]

@Greg_Deckler  Hi Greg, I am trying to find wind direction on PowerBI. To do that I need arctan(V/U) and then convert it into degrees. I cannot have a negative degree so I need it to go around the entire unit circle (0-360). Do you have any sugguestions? Note: if the value of V is negative, the component is south. If V is positive, the component is north. If U is negative, the component is west. If U is positive, the component is east.

[Greg_Deckler]

@Anonymous OK, so ATAN2 should work for you if you plug V in for y and U in for x I believe.

[klago]

Thanks Greg!