After much research and practice I have found a way of creating a definition on grasshopper which produces the flowing and undulating forms that I had in mind from the start.
Point attractors pull a surface to a point by a certain degree. Below you can see the first basic form I created using this technique. It uses two points to attract a surface. The function then tells a vector component to increase the amplitude of a grid of z axis vectors by x amount as the distance x increases from the point. You can then move the points of a surface grid by the amplitude of that vectors and create a surface from this grid of points creating the undulating surface.
After further exploration, I found various different variations on this definition which allow for more attractor points, uses a simpler function that is easier to follow and subsequently easier to control. Below is the best definition that I have found. It allows you to use as many points as you want as attractors and you can even use a curve to attract the surface.
You can also see in the picture how I can use the data from the planet (this one was earth) to create a set of points with can then be used as attractors, defining the form of the undulating surface. Below is the result.
I am really pleased with this find and result. It is the sort of form I had in mind when I originally set out to create these forms from data. It represents the data very nicely as well I think, each form will be different due to the differently placed points created from the data.
In addition, to this I found another way of creating these interesting point attractor surfaces. This is using a Sine Funtion Graph Mapper. Below is the definition-
This creates wave-like forms where the wave pattern originates from the set points. This get really interesting when there are multiple points, see below for renderings-