LTE: Letter to the Editor
Professional Surveyor Magazine - July 2011
First of all, I think it’s important that the editor of a survey magazine actually be a surveyor! Good work, and keep moving forward! Second, I’d like to commend you for your coverage
of NSPS Surveying USA. I serve as the NSPS governor from WA and was very active in the festivities out here.
R. William Glassey, PLS
Under Attack? Editorial
While much of your editorial provides notice of significant jurisdictional concerns, it is my opinion that some of your editorial language is under-researched and only serves as an inflammatory wedge between the land surveying and predominantly civil engineering professions.
Many states, including Wyoming, have in place statutes and administrative rules defining land surveying engagements that can be accomplished under the direction of a licensed professional engineer. It is presumptive that these laws properly consider the welfare of the public that becomes our clients. The key to the successful, ethical practice of any professional is performance within capability, not the nomenclature of the service or the community served.
It is incumbent upon both engineers and surveyors to know the limits of their capabilities, as well as the responsibility taken for the data used in their endorsed professional service products, including data collection means and methods. Failures in those areas are well documented in both professions, and should not serve as a basis for such pointed segregation.
—Kevin D. Jones,
PE, PLS, M.NSPS, M.NSPE
Thanks for reading and offering your thoughts. While you acknowledge that much of my editorial regards legislative concerns that are significant, you chose to focus on the portion that relates to the situation in Rhode Island. As both a surveyor and an engineer, that makes sense and gives you the particular perspective to see both sides of the issue. While my column wasn’t intended to be an in-depth analysis of any of these situations, I felt they were worth bringing to our readers’ attention with the best information I had available and recommended that readers check with the local societies for further information.
Your letter indicates that my editorial was inflammatory and drives a wedge between surveyors and engineers. I respectfully disagree with that opinion. This magazine, including me, continues to be an advocate of improving and broadening relations between surveyors and all related professions. The Rhode Island portion was roughly only a third of my column and I feel, based on the information I obtained from the RISPLS, accurately portrayed the issues. In fact, in response to my column, RISPLS president, Edward O’Brien, indicated that “power grab” was “a very apt description.”
I agree that practitioners—whether surveyors or engineers—should practice only in those areas in which they are competent, no matter what the license says. However, as you indicate, the general practice areas are typically defined by each state. That was the case in Rhode Island going in, but, apparently as a result of efforts by the engineering community in that state, the limits of those practice areas may change.
Engineers may, or may not, be competent in those practice areas in question; that’s not my decision to make. I called attention to these situations because surveyors do need to be protective, to some degree, of our profession and practice areas. But these situations serve to illustrate the bigger issue of my column, which is that surveyors have an enormous public image problem and virtually no one—from legislators to, yes, even some engineers—recognizes the importance of what we do. And just to be clear, surveyors need to work with engineers, and anyone else we can get on board, to change that.
Icefield Surveying History
In March, your magazine published an article by Kris Carber, "Hot Research Cold Climate.
” It was an interesting read for many, including past participants in the Juneau Icefield Research Program (JIRP) like me.
I participated as a student in JIRP in 1988 and 1990. For many years, including during my two summers, professor Dr. Walter Welsch from München led surveying activities on the icefield. He
also found the article interesting but identified some discrepancy with the actual JIRP surveying history. I have forwarded his email (at his permission) so that you may be able to appreciate the historic context of his and his Bavarian colleague’s contribution to this special program and place.
Keith K. Daellenbach, MSME, PE
In response, we are running the letter from Dr. Walter Welsch:
“In 1981, the University of German Armed Forces (UniBw; Institute of Geodesy, professor Dr. Walter Welsch) started collaborating with JIRP by sending its own personnel—namely geodesists—and equipment to provide support for interrelated disciplines represented on the icefield: geology, glaciology, and geophysics.
I do not remember that the other disciplines (botany, hydrology, meteorology, remote sensing, cartography, and geoinformatics) took advantage from the geodetic activities.
The Technical University of Munich (TUM) came into play only in 2001 when I (after 21 years of service to JIRP) retired and found the Institute of Geodesy of TUM. Professor Dr. Thomas Wunderlich was helpful with my Institute of Geodesy (now chaired by professor Dr. Otto Heunecke). From then on, both the institutes of UniBw and TUM keep sending scientific personnel
for JIRP. The Bavarian Office for Surveying and Geoinformation did not send anyone for JIRP. It was I who personally invited Klaus Blachnitzky after his retirement to join me on the icefield in 1987 and 1988.
Maybe that all this is not important but I think the story should be described correctly.
Dr. Walter Welsch
Editor’s note: Last summer, both new and veteran researchers participated in the program, including Ronny Wenzel, a graduate engineer from the University of the Bundeswehr in Germany. Wenzel also weighs in on the project with this additional information to the original article:
The mission of the Foundation for Glacier and Environmental Research (FGER) was to understand the dynamics of glacier systems as they relate to climate change since 1946 and includes measuring velocities and surface elevations of the glaciers. The research work concentrated—and
still is concentrating—on climate change and global warming aspects.
Looking closer at the glacier/climate relationship, the advancing or retreating of glaciers depends on many factors—the kind and amount of precipitation, amount of ablation during the summer, the accumulation area of a glacier due to higher altitudes, and its location to a coast. Taku Glacier for example, has a big accumulation zone with large tributary glaciers (Demorest, Southwest Branch, Matthes Glacier, and Northwest Branch) where Mendenhall Glacier has a small accumulation area. But both are located on the wet side of the icefield while Llewellyn glacier on the other side of the nevè (upper part of a glacier) has less precipitation and therefore a higher rate on negative height changes.
Climatic phenomena like El Nino/La Nina, and Pacific Decadal Oscillation have also impacted glacier behavior. Geodetic measurements are one method to determine changes (velocities, surface heights, ablation). Additionally, mass balance, remote sensing, hydrological and meteorological observations are needed to understand the “big picture” of glacier changes.
On another topic, the article mentioned transforming static GPS work into the ITRF and tying to IGS stations—information that I’ll expanded here.
Some of JIRP reference points have been regularly observed with static GPS measurements. First, the goal was to combine the different existing local survey networks, which was successfully done by this method. The second goal was created a couple years later (from 1995 on), hooking up the
icefield survey network into a global reference frame to determine the amount of plate motion/tectonic movement, especially vertical velocity which is positive (uplift) due to isostatic rebound taking place in southeast Alaska.
Therefore, long-term observations of several days in a row over a series of annual repeat are conducted. The evaluation is done first on daily solutions, then combination of daily solutions to an epoch solution (every years campaign) and further to campaign solution (combination of several campaigns) where ITRF station coordinates and velocities are determined. The
evaluation considers massive additional information like earth and ocean tide models, ionospheric and tropospheric models (accuracies of several millimeters are received). There is a net of IGS sites used in the process, but breaks in the time series of the IGS sites have to be considered as well as anomalies in the GPS measurements themselves.
As to the article’s mention of TerraSAR-X and creation of a global Digital Elevation Model (DEM),
the homepage of Infoterra www.infoterra.de
has more information about the TanDEM-X mission http://www.infoterra.de/tandem-x-satellite
(creating a global DEM till 2014) and the SAR technology http://www.infoterra.de/radar-imagery
. Also check out the available documents on the right hand side of the homepage or contact the Infoterra cpompany for detailed information.
The TerraSAR-X and TanDEM-X satellites are flying in an extraordinary formation (HELIX formation) that never has been done before. The global DEM will be much more precise than this from the Shuttle Radar Topography Mission SRTM 2000 and also will cover higher latitudes (SRTM only up to 60°N/S). While local DEMs can be derived by optical satellite data (e.g. "Reference 3D", a product of Astrium Services), the use of TerraSAR-X alone lead to a radargrammetric DEM, the TanDEM-X mission will provide an interferometric DEM.
The article mentions using total stations in the 1980s, but being limited by instrument range and extreme refraction from the glacier surface. I will explain how these items affected them/the total stations and what they may have done to address these issues, resolve the problems, etc.
Theodolites and later tachymeters (theodolite plus electronic distance measurements) were used in the Pre-GPS phase of survey work within JIRP. Since both are optical/electro-optical systems, their accuracy depends on temperature, moisture, pressure and visibility. Also on glacier
surfaces, heat waves are usual on sunny days and can affect the observations, while on rainy/misty days site-to-site-visibility from the survey instrument to the survey reflectors can be problematic.
This kind of survey in alpine regions had been a real challenge. To resolve these problems, surveyors had a tight (local) net of reference points where tachymeters could be implemented and a short time schedule used due to atmospheric conditions.
As another side note, public television (PBS) has a documentary by Chip Duncan on the Alaska project, with more information available at www.duncanentertainment.com
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