Bearing from one point to another on 2D number plane Title says it all, I'm looking for the formula to get the bearing from one point to another on a number plane. I have found examples of this for lat/lon around the earth but that's not exactly what i need.
Thanks
 A: Exactly what is a "bearing" to you? Compass bearings are typically quoted with 0° meaning due north and increasing in the clockwise direction, whereas in mathematics in general the convention is to consider 0° to be due right, and increasing counterclockwise.
For a compass bearing, the conventional answer is $\tan^{-1}\left(\frac{E_2-E_1}{N_2-N_2}\right)$, where $(E_1,N_1)$ and $(E_2,N_2)$ are the (easting,northing) coordinates of your two points. There are various points to keep in mind, though:


*

*Your arctangent function probably gives values in radians, which you'll have to convert to degrees yourself.

*If the northings are equal, you'll end up dividing by zero. This needs to be handled as a special case, answering 90° or 270° as appropriate.

*The formula also cannot distinguish between a direction and its direct opposite, so you need to add 180° if $N_2<N_1$.

*Directions in the northwest quadrants will end up as negative numbers between $-$90° and 0°; you'll want to add 360° to those to make them look like ordinary compass bearings.
If you're looking to create a computer implementation, see if your programming language has an atan2 function  -- it will take care of points 2 and 3 for you automatically. Typically it should be called as atan2(e2-e1,n2-n1), but I've heard rumors of languages that need you to give the arguments in the opposite order. 
