Hacker News Reader

Comment by dimitar | Hacker News Reader

I upvoted this article because it is really interesting, but unfortunately I disagree that nomography can be relevant today. It is forgotten so easily because its not worth the effort with the availability of computers. Computers aren't hard to use and to learn how to use. Try doing through the exhaustion of doing numerical calculations for a day with a slide rule and nomograms to see why.

View on HN

Have a look at the nomograph in this paper: http://eetd.lbl.gov/ie/pdf/LBNL-1519E.pdf

The anthrax attacks in the fall of 2001 brought to light a number of uncertainties about how to tell whether a building is clean enough to re-occupy (How effective is sampling? What's the anthrax dose-response curve look like? What's the distribution of spores in a building?, etc.).

As part of his investigation, a colleague of mine constructed the nomograph in this paper, to illustrate the tradeoffs involved. By presenting the uncertainties graphically, the nomograph helps visualize the tradespace, in a way that simply running multiple numerical calculations won't necessarily do.

By the way, this also shows that these are not an entirely lost art.

I disagree with the sentiment that nomography has lost relevance. Anybody worth their salt doing interface design for complex systems is exploiting these principles and combining nomography and computing.

For example, a power plant is littered with sensors, reading various pressures, temperatures, valve settings, etc. The traditional interfaces—a dial for every value, as per Three Mile Island—does not help a human operator in understanding the relationships in the data. Today, interfaces are designed to better explain how different parts of a system interact, and a nomograph can help an operator build a better mental model of how a change in a series of inputs affects an output.

A simple calculation on a computer can produce all of the numbers defining the operating point of a turbine, but a good nomograph will convey the physical relationships of the system.

I realize these types of displays aren't seen by most people on a regular basis, but they're far from irrelevant.

I imagine something like a dynamic bode plot, from which you can judge the stability of a system.

But that is a plot of data, not an analog computing method on paper. You can simply improve the presentation or organization on data. I suppose operators have computers nowadays :-).

I think nomagraphs could be very useful in realtime dashboards, where one needs to convey several interrelated values and their relationships simultaneously. Moreover, many engineers prefer nomographs because they're actually faster and more intuitive than trying to solve a problem with a computer. That's why they teach you how to use psychrometric charts in thermodynamics and Smith charts in antenna design (or at least I was taught both ~8 years ago).

Psychrometric charts where an important part of my thermodynamic lectures last semester. In engineering they are pretty useful, both because their accuracy is sufficient in many real-life situations and they give you a very good understanding and guessability for the complex formulas you are using.

What I’ve always liked about nomograms, even more than their (1) usefulness for directly calculating as a practical tool is that they (2) make numerical relationships explicit/concrete, and (3) show an entire multivariate possibility space at once.

This has advantages for someone trying to understand a system over both symbolic equation representations, which are very abstract, and cartesian type graphs, which often are not good at plotting more than one or two variables at once.

I agree with you that with fast interactive computers it's possible to come up with other possibly better kinds of graphical representations, but the creators of those can still learn a lot from the design of nomograms.

These could be really useful to include in spec sheets for various solid state electronics components. They always include graphs of current and voltage characteristics, but perhaps including a nomogram instead (or as well) could help people understand the properties of the component.

They also could be really helpful to teach graphic learners about how certain relationships work -- I am certain I would have understood many concepts much faster with one of these -- particularly in physics.

Reply on news.ycombinator.com