Guest Column: One Size Does Not Fit All
It is still early out, and there are clouds and a threat of weather here in north Arizona. I have just studied the December issue of POB and found it to be engaging with several articles that are good brainfood. I have always found Dr. Paiva and his presentations to be articulate and well founded, so I concur with his assessment of the survey profession. I likewise enjoyed the earlier article by Pat Naville, and can confirm the wide range of questions you get when you are in the public sector, some entertaining and a few severely stressing.
As 2015 has ended, I hope your year was profitable. I had a good year, notwithstanding the reality of the economic situation our country finds itself in. I was in Phoenix recently and was nicely surprised to see noticeable construction activity throughout the Valley of the Sun.
The December POB has an article (response) by J. Allison Butler that honors me by mentioning my name in regard to an opinion that I voiced earlier in the fall. We are in the midst of a serious discourse on our profession and the future of surveying. It is conference season, so I would suggest that this topic be a roundtable discussion item for those of you who are involved at these conferences.
Our world is becoming increasingly dependent on technology, particularly the GPS component of the tools we use. I am just as dependent on GPS tools as the rest of you, so I would like to share my observation regarding this movement to licensure for those disciplines that “measure.” The past year, POB had many articles regarding the world of measurement — in mapping, GIS, data collecting, etc. The postulation seems to be that since we all are using the same tools for our work, all of us should then be eligible for the sanction of license as surveyors. This is against the heart of that sacred trust of license as “Surveyor.” I respectfully would voice my opposition to open licensure.
Old Lesson Rings True
This is the time when I go through the stack and weed out all that paper that I have collected over the year. In doing this, I ran across a workbook from a workshop by Michael Dennis, PE, from more than a few years ago.
Some of you know which workshop I refer to. I remember the workshop not being “popular” since a successful adventure in Michael’s session requires a strong capacity in mathematics. But the heart of the workshop was the many pitfalls with GPS data, and what the process is to identify those components of the data stream and how to resolve the “numbers” so that you could defend your data. One of the topics was the “grid to ground” methodology and what that meant insofar as the confidence in your data.
What I “got” from this workshop was the serious issue of taking “dynamic” (GPS) data into a “static” (flat earth) world. Machine control, construction staking, boundary location and mapping come to mind as those survey processes that are affected. Like many of you, I use the “numbers” right out of the box. However, my work is confined to small sites, usually an acre or less, but the correction is still on the order of at least 0.03’ after doing the math.
What brings this up for me is that article in the December POB that features work in a remediation site and the statement that all layout was accomplished from machine GPS solutions and tolerances were within a half-inch. I would surmise that the data and control basis were well formulated to achieve those results. I don’t know that I would make such a statement and show that I was using the bucket of an excavator as my reference stick.
Another Lesson in History
If you know your survey history, you will recall that early geodesy (surveying) was scientific in its approach. Read up on the methodology of establishment of those initial baselines that form the basis of the rest of our state plane network. This involved the use of Invar rods that were only used for measuring, with supports at each end with proper attention to atmosphere (temperature) and solar effects. What do you have in your field book that identifies site conditions? Do you even keep a field book? How do you go about your QA/QC procedures to validate the data?
Our equipment has tremendous capability, but it also can tell us we are in Bolivia when we know for a fact that we are in Maricopa County, west of Buckeye, Ariz. Just because the numbers are within the parameters you set and are expecting does not necessarily mean that the data is valid.
If you are working in a closed system, you will not know that you have bad data. A closed system is what GIS usually is, where you have a dataset that is within your specified parameter and is consistent within itself. This is not bad; it just is data within a specific bound and the quality is based on your criteria. This is the old “5000, 5000, 5000” coordinate geometry basis that we all are familiar with. Technology today gives the capacity to work in numbers that just a few years ago would bring us to tears and stress out the calculator. So, in our continuing discussion on what surveying is, remember that surveying is not “one size fits all” and that your data is not applicable across all aspects of survey.
As closing, let me pass on this tidbit: There is a new surveying association in Arizona. Check out United Surveyors of Arizona at usofaz.org.