Change Coming for State Coordinate System
There’s an old line about perfect being the enemy of good. It is also paraphrased as perfection being the enemy of progress. I recently had occasion to examine both versions of the phrase.
A reader commented on POB’s September cover headline “Achieving Absolute Accuracy for Alpine Railway.” While acknowledging the article as “excellent,” the reader pointed out it “captured the ideals, work, and goals of the Alpine rail road project.” Thank you for that. Then the “but.” There’s always a “but.” The headline did not do the article justice, the reader said. “In surveying there is no such thing as ‘absolute’ accuracy.”
Here’s where “perfect” and “good” first come into conflict. Writing headlines is both art and science. The mechanical, factual science tries to convey as much information as is possible in a small space, and to do so accurately. The art wants to bend the science a little when there is a perceived opportunity to pique a little more interest through some hyperbole, word play, or other device. In seeking to extend the alliteration that comes from “Achieving Accuracy for Alpine Railway,” the obvious addition is “absolute.”
Our reader had some rail experience (as do I). I found the comment interesting that, “Nowhere did the need for extreme accuracy enter the calculations for rail alignment. Safety, freight, passengers, curvature, superelevation all played a part in the final rail alignment. Nothing absolute in any of these inputs.” I am hoping this comment has an implied, “but accuracy should be the goal of the calculations.”
In POB’s October issue, we featured a long discussion of the blueprint for updating the National Spatial Reference System. Parts of the discussion focus on accuracy that is so tight there isn’t even room for it to squeak. The size of the dimple in a survey marker comes to mind. I spoke to Allen Nobles of SAM Surveying and Mapping LLC about the NSRS update. Allen had suggested POB put out the word that “your coordinates will move six feet in 2022.”
In the history of the National Geodetic Survey, the labels tell the story. NAD 27 was superseded by NAD 83, and that was late by seven years (more like NAD 90). There was apparently little appetite in the U.S. for another undertaking when the International Earth Rotation Reference System was adopted in 1988. Did “perfect” get in the way of progress? If so, we got over it, and the intervals reflected in the numbers on the updates show us moving on quickly after that (in relative terms).
Whether or not you see a need in your work for the centimeter levels that are coming, the important point Nobles stresses is that all surveyors will be affected because state plane coordinates will be affected. Even this won’t deliver absolute accuracy, but it will provide a new “best” as we continue to strive for perfection.
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