Converting grid ref to heading/bearing

Hi, I'm new, I hope this is the right forum for this!

I am trying to re-create a model I wrote years ago, (lost the source code), One requirement is an algorythm that will calculate the angle, between two points on a plane, from the x,y coordinates of the start and finish; I will be writing in Pascal or Object pascal, but I am NOT asking for code, just the algorythm. However, if you do NOT have the design but do have code, I will be happy to look at that

Thanks,
Jim

I think you have to provide some additional information. Two points make a single line or at least can do so.

Thanks s_m_a ??

You're right! The bearing I am calculating is between the line specified by the two points and the X axis West to East. That axis being zero degrees.

This is dictated by the progarming language that I favour where the 0 / (nought) axis is horizontal, not vertical like we use in normal navigation.

I hope that is clear. Sorry for the obvious omission.

I fear I need a spell checker on this interface!

Thanks and best wishes, Jim

Sounds like the good ol' conversion from cartesian to polar coordinates (which is independent from any programming language anyway).

HTH

Thanks eri523,

I had not come across te cartesian to polor convertion thing but it is allmost exactly what I am doing now with one great difference.

I am NOT calculating the angle as if the start point is at 0.0. If I do that and simple translate the start x,y, it makes my method far neater. Thanks for that.

I think there is another problem with the code which I have not discovered the cause of, I'll be back!

feralipod