What is the correct term for the type of performance chart where curved lines are followed? What is the correct term for the type of performance chart where, from a starting location, curved lines are followed to various reference points to eventually find a solution?
For a specific example, the type of chart I'm asking about can be found in the Pilot's Handbook of Aeronautical Knowledge as Figure 11-23:

Background to the question: I would like to reverse-engineer a performance chart in order to use it in a spreadsheet. I have no idea how to do this but if I can discover the name of the type of chart it is, I can begin by looking for notes from other people who have attempted the same.
The correct term is nomograph or nomogram. Thanks Gerry!
Also, thank you to Peter Kämpf and Dean F. for helping to answer my actual question, instead of the one I asked.