Hi John. The only thing I’ve seen on that is the paper http://eldredgeengineering.com/Reverse%20Engineering%20Nomographs%20Paper.pdf but the author’s approach is definitely ad hoc––he knows the form of the engineering equations and he has a nomogram that has a grid that can easily be separated into x and y components. The general method seems to be curve fitting based on the expected form of the equation from the configurations of the scales. On the other hand, it may be possible to deduce the x- and y-elements of the determinant for each scale (perhaps by measuring and curve-fitting the spacing of the values), plug them into their places in the standard nomographic determinant, and then evaluate the determinant to find the original equation. Or you might create a table of results for two variables keeping the third variable fixed in value (by measuring off the nomogram directly), then plot these and use a curve fitting program to find the equation for each value of that fixed variable, then repeat this to find the full equation when the fixed variable has different values. — Ron

我非常感谢你 — Ron

That’s odd—when I click on the link I see the book contents viewed under the “Read this book” tab with a “Download PDF” link to the upper right. Clicking this download link results in a single PDF file that includes the pages that are missing for you. Perhaps Google is reading a cookie of mine to bring me back to where I was. I know there is more than one edition of this book on Google Books—I chose this 1918 edition rather than the 1921 edition because the scan was sharper and the later one looked identical but just part of a book series, so perhaps your search is ending up at a newer edition that isn’t in the public domain yet. In any event, I’ve read through the Google conditions at the start of the file and there is nothing preventing me from posting the PDF file if I leave in the Google watermarks, so I’ve uploaded it to my website. You can download the 6MB file at the following link (I’ve updated the link in the post as well):

The book is in two parts. The first part - the one that contains the nomography section - is missing 8 pages: p100-103 and p111-114. This is not disastrous, but the missing pages cover some useful cases.

Is it possible to give a rough outline of what was involved in the nonprojective transformations you refer to? I suspect it’s not feasible to do so here, but I figured it couldn’t hurt to ask.

Glen and I have corresponded on this topic since this comment was posted, and I have looked in more detail at using the Weierstrass’ Elliptic Functions to create a nomogram. I’ve posted a new essay describing this at http://myreckonings.com/wordpress/2008/02/24/a-zoomorphic-nomogram/. — Ron

Thanks, Glen. There’s nothing in the queue for nomography at the moment, but I’m continuing to look into designing them for particular uses. I suspect there will be another post on nomography in the future, but not for a couple of months at best. — Ron

I understand every word of this, but George doesn’t. Wonderful work.

Barb