hallo,
i have some geocoordinates which i wanted to do something within vvvv.

the formula for converting geocords in cartesian is:
rho = Earth radius = 6367449 m
theta = longitude
phi = latitude

x = 6367449 * sin(longitude) *cos(latitude)
y = 6367449 * sin(longitude) *sin(latitude)
z = 6367449 * cos(longitude)

I am not sure if i could do something with that then in vvvv or if i have to map that further in something else.
And I was looking for sin() and cos() nodes, but could not find.

Or should I better write one own node with javascript?
If that is better, how can I do that?

as the earth radius is just a scaling of the output vector you could write it like this:

x = size * sin(longitude) *cos(latitude)
y = size * sin(longitude) *sin(latitude)
z = size * cos(longitude)

where size is your sphere radius. apart from that, you could use the node Cartesian (3d) which will convert longitude and latitude to xyz coordinates with your formula, but the angles are from 0…1.