Hi
If dyad=[x;y;z]
then the bedpost convention is obtained in matlab using:
[ph,th] = cart2sph(x,y,z);
th=pi/2-th;
Cheers,
Saad
> On 4 Oct 2017, at 14:26, Max Wichmann <[log in to unmask]> wrote:
>
> Dear Fsl Team
> I need to know the exact convention for phi and theta of the bedpostx output, because I use some matlab functions (in matlab phi is referred as elevation angle from 0 to +180 degrees (co-latitude) and theta as azimuth from 0 to 360 longitude). I know from the image in your user-guide documentation that in Fsl phi is referred as azimuth and theta as elevation but it is not said if wether they are longitude, latitude or co-longitude, co-latitude. So matlab not just switched the names phi/theta, which is not the problem, they also have another convention for their elevation angle compared to some online calculation websites which using latitude convention.
>
> So if Fsl uses also a different convention compared to matlab I guess I need to do: 90- elevation (value calc by matlab) before do calculations with fsl?
> In my work I want to calculate via matlab the spherical coordinates of an dyad sample thus I can use make_dyadic_tensor command afterwards.
>
> Thank you very much for helping!
> Best
> Max
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