Generating a contour/heatmap like density plot

[pkrina1990]

I have three input variables; F, U, N, whose values are independent of one another and are triangular coordinates that I input into the code. I was able to use ternplot to generate the graph I want. However, within that data, there are points at the corner of the triangle that overlayer perfectly, thus I want to generate a heat map like plot using ternpcolor or ternsurf that would highlight regions with the most responses (even those that perfectly overlay).