2014

Measure for Measure

A Response to "Measuring the Land"

by Philip Stein

"In November 2003, I wrote about a surveyor's base line--a method for calibrating measurements of the land (geodesy) and providing traceability of those measurements to national standards ("Measuring the Land," p. 74).

After that article was published, I heard from Phil Painchaud, a founding member of ASQ's Measurement Quality Division and one of the division's experts in metrology education. Painchaud has played a central role in establishing this country's college-level measurements curricula and getting them approved and installed at various institutions, most notably Butler County Community College in Pennsylvania and California State University at Dominguez Hills.

Painchaud wrote me a long, personal and fascinating letter about some lesser known events in the history of geodesy during the middle of the last century. With his permission, I would like to share his letter with you:

"Again our technological histories seem to cross paths. I have a certificate hanging on my wall that states I successfully completed Geodesy 491 at Los Angeles State College (now California State University-Los Angeles) in May 1952. Just how I came to receive that certificate is going to take some explaining.

When I first joined a major aerospace company in 1948, I was assigned to a secret group that was doing basic research on the guidance system for an intercontinental missile. It was to be a fully automatic, inertially stabilized celestial tracking guidance system. My immediate superior was Dr. T., an astronomer and optical physicist of considerable note. He had completed his doctorate under George Ellery Hale at Cal Tech and had worked on the design of the 200-inch reflector at Mount Palomar.

Since our guidance system was to be celestially oriented, Dr. T. insisted we work with celestial rather than terrestrial coordinates. Unfortunately, the only places in this country where celestial coordinates were known to any degree of accuracy were at the couple dozen prime points established by the Coast and Geodetic Survey (C&GS) and at a few major astronomical observatories. The observatories needed the data to establish the mounting angles of their equatorial telescope mounts, and the prime points were used to establish the starting point for all the land surveys you mentioned in your article.

The extensions from the prime points were run either by local jurisdictions, such as states, counties and cities, or by private land surveyors. Rarely were these equipped to measure and take into account the anomalies of gravity, particularly the vectorial anomalies that occur along the lines of extension and can be of considerable magnitude. Therefore, when the local surveyor reached his area of interest, there was often a considerable variance between the true celestial coordinates and the extended terrestrial coordinates.

In most practical cases, this variance was of no consequence in the legality of the land title, but in our case, these variances were critical, especially during the testing phases. If we entered known terrestrial coordinates of a target and guide celestially, the test vehicle would probably miss the target.

To prove that point, we set up a stable concrete pier in the parking lot of our plant in Southern California. Fortunately, we had a Los Angeles County prime point (secondary to a C&GS prime point) just a few blocks away. By precise surveying, we transferred its coordinates to our pier. We then hired an expert in celestial coordinate determination to come up with the celestial coordinates of the pier.

On his first try, the expert was able to quote us a figure Dr. T. claimed was accurate to "within 10 feet in absolute space" (meaning there was no terrestrial reference). Later, with repeated redeterminations and extensive statistical analysis, he was able to reduce this uncertainty to about 6 inches. But with either uncertainty considered, Dr. T's point was proven--the difference at our pier between the celestial coordinates and the legal terrestrial coordinates was 3 miles!

That meant every one of our planned test targets was going to have to be celestially determined. The tests were to be between a departure point close to home and a distant target. Both points needed to be determined, as did the locations of the tracking radar stations. Elsinore Peak in Southern California was selected for the departure point, and Tempe Butte in Arizona (that big hunk of rock sticking up as you approach Tempe from Phoenix) was designated as the first target in an increasingly distant series of targets.

The first tracking radar location designated was Santiago Peak in the Cleveland National Forest. That made things a little easier because Santiago Peak was the C&GS prime point for Southern California and was normally redetermined about every 10 years (it moves approximately 4 to 6 inches every 10 years or so). We could live with those figures so we did not have to determine the site ourselves.

We then rehired the expert--the eminent Donal B. Pheley, retired chief field officer of the C&GS. He was the one who had done the precision survey of the San Bernardino base line for use in the precise determination of the distance between Mount San Antonio and Mount San Gorgonio for Albert A. Michelson's classic velocity of light determination. His last celestial determination job before retiring was that of the Griffith Park Observatory in Los Angeles. When we hired him, he was a professor of astronomy and physics at Los Angeles State College.

His previous job for us, determining the celestial coordinates of the pier in the parking lot, took place just feet from the plant where we had access to all kinds of support and creature comforts. The next two jobs we wanted him to perform, however, were to take place in the field--one was 500 miles from home base, and the other was on a normally inaccessible mountaintop 50 miles from home base. All support items, instruments and personnel would have to be transported to and maintained at each site. The Arizona determination was scheduled for the Christmas holiday and the Elsinore determination, one month later.

Whoever was assigned to the Arizona mission would miss the company's traditional Christmas vacation. Guess who got the job of heading that safari? I had been with the group only 10 months and was low man on the totem pole, but it proved to be one of the best assignments I ever had. I not only learned a tremendous amount from Pheley, but I also found out I had a natural flare for the logistics of assembling and managing field expeditions.

That man Pheley was fantastic. He taught me so many things that were to become invaluable in my later practice of metrology. He carried all his computations to 10 decimal places so there was no chance of error due to accumulative rounding off. Of course, there was no such thing as a PC in those days, so all his computations were done with paper and pencil and a desk calculator, if available.

I had packed a 10-column Frieden square root extracting desk calculator (advanced technology in those days) as part of my equipment for the Arizona trip, and I thought I was rather proficient with it. Pheley, on the other hand, used a ponderous book of seven-place log tables. Each night after he completed his observations, we sat down and calculated his algorithms using the observation data. He beat me every time. He was able to look up the logs, add, subtract, multiply or divide them, look up the antilog and write out the result before I finished entering the basic data. Nevertheless, he liked to use my results to check his own.

After both missions were complete, we hired a young fellow fresh out of Berkeley who had studied the use of the Bamberger Bent Elbow Telescope--a newer and more flexible instrument than the two ancient devices Pheley was forced to use. It allowed us to do the job with one instrument and fewer calculations. Our new fellow persuaded the university to loan us its Bamberger, and we were able to proceed without having to rehire Pheley and without the attendant security problems of having an outsider so close to highly classified information.

But I was unhappy. Though I could handle the logistics and administration of each of the resulting field expeditions without much of a hitch, I still didn't know enough about what we were doing. I persuaded Dr. T to approach Pheley and Los Angeles State College about instituting a geodesy program. As it turned out, Pheley already had such a program put together but had not been able to attract much interest in it on campus. The administration agreed to formalize his program within its extension program, allowing Pheley to teach the course in the evenings at our plant. And that's how I earned my certificate.

I still have the textbook, Geodetic Control Surveys, second edition, by H. Oakley Sharp (John Wiley & Sons, 1943). Pheley used this book for collateral reading and some homework, but the real meaty stuff came directly from him and his vast experience.

As the one-on-one teacher I had gotten to know on our field trips, he was unsurpassed; as a classroom instructor, I found him a bit too formal and stiff, but he was very effective, interesting and practical. While he had spent most of his life working with the classical methods, he was receptive to and tolerant of the newer technologies in the field. Long-range aid to navigation, short-range aid to navigation and other electronic methods were just emerging, and he told us his methods would soon be outdated and the newer ones would take over--and he was right.

One of the first things we learned from him was the proper definition of geodesy:

Geodesy is the science of the measurement of the surface of the terrestrial spheroid and the precise determination of position.

Geodesy is the basic science that underlies surveying, cartography and navigation. I believe it is the oldest discipline of metrology. When man ceased being a nomadic hunter and settled down in an agrarian environment, he needed to measure his land."


PHILIP STEIN is a metrology and quality consultant in private practice in Pennington, NJ. He holds a master's degree in measurement science from George Washington University in Washington, DC, and is an ASQ Fellow.


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