This is fantastic! Started to break it down in detail.
I thought I understood what was going on, but it seems I must not understand what is happening with the line traces. I tried changing the resolution of the render target image (so that it would be the same as my landscape-1, and then mapped the texture 1:1 to the landscape. I was thinking that would give me 1 trace per pixel with each pixel representing a square on the landscape. I also switched the blueprint to get the extent bounds of the landscape instead of the Box Collision Component in the blueprint.
When I changed the render target to a high resolution, it only partially renders the image, or it seems that way, most likely rendering entire image, line traces just are not hitting anything or rendered to incorrect parts of texture?
This might be a bit my level. I think its the grid execution I might not be understanding, or the draw texture node. Trying to read up on the draw texture and draw canvas nodes.