reprojecting bearings

Question

Hi,

So I have a point dataset on circulation for the whole world. The data is unprojected. One of the attributes is a bearing for the atmospheric circulation, with a compass direction.

Now I want to reproject this, to for instance Winkel III - is there any way to reproject it so that the value 0 in the bearing attribute still points towards north? Reprojecting the location of the points is simple, the crux is how to recalculate the bearings!

Hope you understand what I mean!

Any tips are welcome!

KimOllivier · Accepted Answer

What I think you want is to convert the true north value to a new field with a grid based bearing.
If this is the problem you are in luck - there is a command for that! Not sure when it appeared 10.0(?)
That refers to an earlier obsolete tool Calculate Geodesic Angle if you are still on 9.x

CalculateGridConvergenceAngle_cartography (in_features, angle_field, {rotation_method}, {coordinate_sys_field})