# arctan2 function in Feature Calculator

To compute the angle between an object and its parent process object, the **arctan2** function would be great in the eCognition Features Calculator.

Arctan2 returns the arc tangent of the two numbers x and y (i.e. object coordinates). It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result.

**arctan2(y,x****)** =

- If x=0 and y<0, the angle is 270° (3*π/2 radians)
- If x=0 and y>0, the angle is 90° (π/2 radians)
- If y=0 and x<0, the angle is 180° (π radians)
- If y=0 and x>0, the angle is 360° or 0° (2*π or 0 radians)

With the this potential string in the feature calculator, users could compute the angle between objects then easily:

*arctan2**([Y Center diff. PPO (1)], [X Center diff. PPO (1)])*

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We will try and get this added for your Christian! Thanks for the recommendation.