Why is the definition of Spherical coordinates in Julia strange

I want to transform a point in a cartesian coordinate system to a spherical one.
I am using the Package CoordinateTransformations.
As I made my first steps with SphericalFromCartesian I noticed that, when writing
transf = SphericalFromCartesian()
i receive: Spherical(r=1.0, θ=0.0 rad, ϕ=0.0 rad).
In Addition the angles are defined in complementary ranges as usual.
My Question is:
Is there a transformation that follows the usual convention. (positive z-axis sets θ=0.0, ϕ=0.0)?

Hi there - from looking at the package source code it seems that a slightly non-standard spherical coordinate system is being used. If you are used to r, theta0, phi0 (where theta0 is the angle between the cartesian vector and the positive z axis, and phi0 is the rotation around the z axis) then you can map from the package output to this system with theta0 = pi/2 - phi and phi0 = theta (or you could write your own cartesian to spherical conversion function, its just a few lines of code).

But I think the answer to your question seems to be no - I couldn’t see a transformation function in this package that does exactly what you want.

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That sounds in line with how I was taught spherical coordinates. Just thought I’d interject that it’s not “strange”, it’s just another convention.


For reference, this has been discussed in Document that for spherical coordinates theta is going from x to y and phi is going from xy-plane to z · Issue #25 · JuliaGeometry/CoordinateTransformations.jl · GitHub (which is considered a prerequisite for v1.0).

The subject was also partially addressed by https://github.com/JuliaGeometry/CoordinateTransformations.jl/pull/68, and has been mentioned in Add Alternative Spherical angle conventions · Issue #73 · JuliaGeometry/CoordinateTransformations.jl · GitHub.

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Thank you all for the answers. I only saw definitions equal to the wikipedia entry till now, that is why I thought that it is the (only) common convention.