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Geodetic Surveying Made Plain

August 31, 2001
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McGray


Plain surveyor discovers new civilization.

Your geodetic surveying reporter visited the ESRI User Conference in San Diego in July, and the scales falling from his eyes got all over his brogans. The convention was dazzling; there’s no other word for it. There was a broad range of products related to imaging and mapping, all displayed at the San Diego Convention Center in force. Especially in evidence were elaborate display kiosks by all the major GPS manufacturers: strong evidence indeed of the future of GIS as viewed by those big hitters.

That realization—the commitment of resources to GIS by the GPS manufacturers—was one of the epiphanies I experienced. Another was recognizing the extensive interest in surveying on the part of many GIS professionals. Sometimes I hear the surveying community express that “GIS guys don’t know about surveying and don’t want to know.” I’m convinced this view is wrong. Here’s a list of the reasons why, as illuminated by the ESRI International User Conference.

Surveying Track Created

Like many professional conferences, subjects are identified by some 40-odd “tracks.” For instance, there is a forestry, wildlife and fisheries management track, a universities and higher education track, an application development track and so on. For the first time, this conference included a surveying track. And this one was the 21st of ESRI’s annual conferences. Included in the surveying track were such topics as:

• Implementing the surveyors’ and GIS professionals’ accord, a panel discussion on changes on the NCEES Model Law for surveyor licensure. (There was some debate about whether "accord” was the right word; there may be more discord than accord.)

• Improving the spatial quality (positional accuracy) of GIS data, a look at specific projects addressing that issue.

• Integrating survey data in a GIS; another application-oriented discussion.

Here’s the thing: those, and other survey-related sessions, were packed—as in standing room only. And the participants were strongly engaged in the topics; interest and advocacies ran high.


ESRI Surveying Coordinator

One of ESRI’s key people, Mike Wier, has been appointed manager of surveying-related stuff. Mike was previously marketing manager, but the subject of surveying was deemed important enough by this largest of GIS-related software firms to need a management level person to coordinate it.


ArcGIS SurveyAnalyst

ESRI announced a product, SurveyAnalyst, as a module of its umbrella ArcGIS system. A demonstration of a preliminary version was, like the other surveying track events, “sold out,” accommodating about two or three hundred people.


And Geodetic Surveying Fits Into This How?

In a couple of ways. First, GIS relies heavily upon coordinate data, and its underlying coordinate systems and datums. Who are the authorities on those systems? The geodetic surveyor. I don’t know anybody more conversant with coordinate systems than Dave Doyle, senior geodesist with National Geodetic Survey (NGS). And I assure you that Dave would heartily endorse a major infusion of coordinate system expertise—that is, of geodetic surveying into GIS.

And there’s more than the practical connection of my coordinates/your coordinates. There is a fundamental connection that has long been recognized by ESRI. Most, if not all, of the product lines ESRI offers carries the brand “Arc” something. Those three letters are not an acronym; they’re a word. I know, I know, that’s almost unheard of in the world of software naming. Why do you suppose ESRI chose that word to be the first syllable of virtually every product they sell? Well, according to my Encyclopedia Britannica, that simple section of a circle was a key element in Eratosthenes’ (3rd century B.C.) calculations of the size of the Earth. His estimations are generally considered the birth of geodesy. Although Eratosthenes’ estimate of the size of Earth was off by some 15 percent, his methods and math were sound; he just needed better measurement tools. Anyway, “arc” of course remains to this day one of the important concepts in all surveying—not just the geodetic kind. So the de facto standard software line for GIS honors the roots of geodetic theory by adopting the very name of one of its cornerstone components. I find that connection striking.

Clearly, there is something going on here in the way of a stronger relationship between GIS and surveying. I don’t pretend to have a bunch of answers, but I think some things are dawning on folks in both the GIS community and the surveying world.


Prognostications

GPS manufacturers, whose prominence at the ESRI conference was mentioned earlier, are bearing down hard on innovative methods to tighten the accuracy of both autonomous and differential GPS (DGPS). The GPS system itself is looking into improvements in technology and such strengthening as additional frequencies. Even the casual observer of GPS has noticed that the system has become more usable—and more useful—as full constellation status, S/A elimination, and new satellite blocks have been implemented.

Can there be any doubt that another order-of-magnitude increase in performance lies in the not-too-distant future? Would you think that, say, decameter accuracy with DGPS will be commonplace soon? I would. How about submeter autonomous? Not preposterous at all, wouldn’t you agree? One need not get too far into science fiction mode to visualize global carrier-phase ambiguity resolutions broadcast to hand-held receivers costing under a thousand dollars. Think of it: a hand-held receiver you buy on the Internet with your credit card today, unwrap it tomorrow, load four AAAAA batteries (they’re new, too), walk outside, and almost instantly get a centimeter-level coordinate based on a worldwide system (GloDat2012?).

Listen up surveyors, because here comes the scary part: when I run that scenario past, say, a fairly savvy non-surveying technical person, his response is, “Oh, cool. Then we won’t need surveyors.”

That is of course not an accurate prediction in my opinion. But, that a non-idiot would give voice to such an idea is certainly food for thought, don’t you agree? I believe many non-surveyors do in fact think of our specialization as being expert measurers, period. The real contribution the surveyor makes, I think we would all agree, is in recovering and evaluating evidence for boundary determination. We don’t just measure the pieces of the puzzle; we put it together. And I don’t see that need ever going away—at least not in our or our children’s lifetimes.

But, I personally don’t like the idea of relinquishing my “expert measurer” job to just any skateboarder with an a Acme GPS Decoder, do you? OK, so how do we play defense with that issue? I’m not ready to call the play yet, but I do know this much for sure: we don’t win the game by refusing to play or by insisting that we, and only we, can make the rules.


What We Have Here Is a Failure to Communicate

Boy, the warden in Cool Hand Luke sure got that right, even though he never even heard of GIS vs. surveying. On an everyday basis I see surveyors looking with disdain upon GIS location data, kind of a “my way or the highway” attitude. Or, “I wouldn’t sully my hands locating an object that only needs to be correctly located to the nearest meter." Look, we already use various levels of precision, right? You don’t locate a topo shot as closely as a control monument or a downtown building corner, do you? Isn’t selection of precision a hallowed principal in the heirarchy of a surveyor’s responsibilities? What’s wrong then with folding one more choice into the precision mix?

Take it from a recent GIS convention attendee, it works the other way, too. There are GIS professionals out there today who are angry at their local surveying community because “they won’t give us the coordinates on such-and-such control monuments.” That the network is not based on current datum, or that a known defect exists, or that the surveyors have been burned before by inexperienced drafters at a utility company mishandling a HARN vs. non-HARN issue, or maybe a surface adjustment factor—none of those matter to this hypothetical but not unrealistic GIS agency. With these kinds of misunderstandings and miscommunications, it would seem that a simple conversation or two could go a long way toward ironing things out.

I for one resolve to make the effort to learn more about GIS. Reading POB Contributing Editor Mike Binge’s columns is a good start. Mike helped me be less baffled by GIS at the ESRI show and is an all around good guy, as well as being a genuine surveyor who happens to work as a GIS professional.

Here’s all I would suggest to my surveyor colleagues: keep an open mind, look for opportunities to do what we do best, and don’t be guilty of failing to communicate.

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