Name of the curvature

1. Jul 2, 2014

manushanker20

I am working on a paper that provides the following formula for computing radius of curvature at a point on a surface.

$$\frac{1}{\rho_c}=\frac{\partial G/\partial S}{2\sqrt{E}G}$$

where $$E$$,$$G$$ are first fundamental coefficients and $$S$$ is the arc length parameter.

Can any one please tell me the name of the curvature the above mentioned formula computes.

2. Jul 4, 2014

Gauss?