Yeah, I think I have some work to do here, I don't *really* know the 2-d distances, only 3-d; I'm trying to create and visualize the lines in 2-d.
What I've got is two tables. One contains a few thousand "start" points having line_id, X,Y, and Z values.
I also have a table of survey points having line_id, "distance" (as measured from the start point on the ground with a hip-chain), azimuth (from the last survey point), and "dip" (being degrees above or below flat "0" from the previous survey point on that line).
If the "distance" is 20, but the dip is non-zero, then I need to first compute the 2-d distance the line should cover. Those facilities don't already exist in 9, do they? Where I would import a traverse file describing degree-changes in elevation over a distance, and the resulting 2-d line segment would measure the correct length in 2-d space?