No such thing as an objective scale for morals... but that is a different discussion.
Perhaps you mean to quantify morality? In which case you measure the badness of killing rather than why killing is bad in the first place (though why things are bad would be how you'd inform your choice for scale.) If you want to measure why killing is bad then you are measuring the validity of the reasons given for a moral judgement ... so "because mommy said so" may be less of a why than "because it may have consequences for the wellbeing for society as a whole".
My point here is that unless you can clearly state what you are measuring, you won't get anything meaningful.
But you are asking about maths:
A sine wave, itself, is a 1D object: notice how it has no depth or width? It's a curved line.
Though it is used to relate two variables so we think of it as a curve with an extent in 2 or more dimensions.
So ##z=A\cos(kx)## tells you how ##z## varies with ##x##... same as any ##z=f(x)##.
You can have functions of two variables: i.e. z=f(x,y) ... and example may be ##z=A\cos k \sqrt{x^2+y^2}## which would be a radial sinusoidal surface - a 2D object which we represent in 3D. A sine wave in 3D would look like ##z=A\cos (k_x x + k_yy+k_zz)## which is a regular sine wave but oriented in an arbitrary direction.
The sine wave is continuous ... so there are no spaces between adjacent points on the curve.
Building a continuous curve from a set of discrete points is called "interpolation".
The study that includes the "dimensionality" of mathematical spaces, and how different parts of that space relate to each other, is called "topology".
Al this is probably overkill for your purposes.
It sounds more like what you want is a morality scale that works along a line like a thermometer does - so you can say one thing described by a host of factors is more or less moral than another thing.
It is likely that morality does not work like that ... but that never stops anyone from coming up with such scales.
You will have N dimensions of measures that contribute to the morality value of an act ... like how many kittens are killed by the act, how many starving are fed, homeless housed ... etc. You want to "map" those values onto a single 1D number line ... so you write ##z=f(x_1,x_2,\cdots, x_N)## ... where the details of ##f## are the particular "mapping" that describes how the different factors you measured contribute to the overall morality.
i.e. for the example - we may naively think: ##f(x_1,x_2,x_3)=x_3+x_2-x_1## for the above examples where ##x_1## is the number of kittens killed, and the other two are starving fed and homeless housed respectively. Or you may say ##z = x_3x_2/x_1## ... how you do the function related to how you think morlality works.
