Q:

Which kind of gradient should I use on a gauge

So I have this gauge in an iOS app that has a linear gradient from left to right on on arc inside of it like this

That works well when I only need the gradient to stop in the middle, but when I want to shift the gradient back a little bit, as you can see, it bleeds the upper green part into to the lower part of the dial since it's only linear and those sections overlap.

My question is this: 
Which kind of gradient should I use that would rotate colors around a circle? 
I know it's not radial, because that would have the same color on the axis in which I am drawing it on.

A:

The term you a re looking for is an angle gradient. This plots the gradient along a circular path and fills the area with it. Lots of image desgin software (like Photoshop) will allow you to make one.

In your case, I'd create one that has the 'split' on the bottom, as in the image.
An alternative in vector software (like Adobe Illustrator) would be to have a gradient stroke, applying a gradient to a path:

