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2012 Chapter Officers
President: Bill Koch [email protected]
Vice President: Kevin Genasci [email protected]
Secretary: Rich Brown [email protected]
Treasurer: Bill Jones [email protected]
Chapter Rep: Keith Spencer [email protected]
Chapter Rep: Jon Scarpa [email protected]
Alt. Chapter Rep: Mike Turnrose [email protected]
Alt. Chapter Rep: Bill Koch [email protected]
2012 Chapter Committees
By-Laws Committee: Keith Spencer
Construction Committee: Landon Blake (Chairman)
Education Committee: Kevin Genasci (Chairman)
Membership Committee: Keith Spencer (Chairman)
Monument Preservation Committee: Mike Quartaroli (Chairman)
Newsletter: Rich Brown (Editor)
Professional Practices Committee: Josh Elson (Chairman)
San Joaquin County Liaison Committee: Kevin Genasci (Chairman)
Stanislaus County Liaison Committee: Rich Fultz (Chairman)
Website Committee: Keith Spencer (Web Master)
2012 Chapter Programs
Boy Scout Merit Badge: Scott DeLaMare (Coordinator)
TrigStar: Bill Koch (Coordinator)
Workshops: Chris Martin (Coordinator)
July 2012 Volume 2, Issue 4
THE PRISM Date: July 25, 2012
Time: 6:30 p.m.
Location: Perko’s @ 901 North Carpenter Road, Modesto
Speaker: Matt Vernon,
Topic: ACSM/NSPS
Date: August 22, 2012
Time: 6:30 p.m.
Location: Perko’s @ 901 North Carpenter Road, Modesto
Speaker: Marti Ikehara, NGS
Topic: NGS update—Recent changes in formats and datasheets
Table of Contents Classes, Training & Continuing Education Page 2
Editor’s Message Page 2
Technology & Info Page 3 National News Page 5
State News Page 6
Classified Page 10
Picture of the Issue Page 10 Puzzle Page Page 11
Up Coming
Meetings!
Announcements GLIS No Longer with ACSM
The Geographic and Land Information Society (GLIS) in transforming itself as a result of the imminent merger of the ACSM into the NSPS. GLIS will no longer be a member organization of ACSM. GLIS’s vision is “to become the national go-to organization for survey-related GIS concerns and issues.” Congratulations to the Newest Land Surveyors Tom Price (LS8920) of Stantec Consulting, Modesto is our newest Corporate Member. His membership has been upgraded due to his passing the LS Test in April. Others within the local area passing the LS test in April: Christian Cintean (LS8941) Chapter Waives 2012 Dues for Unemployed Members At the October, 2011 meeting the Central Valley Chapter voted to waive 2012 chapter dues for any members (or new members) who have become victims of the current economic downturn and are unemployed. Please fill out the Membership Application, enter “Unemployed" on Line 7 for the Name of Firm, Agency or Col-lege, submit your application, and your 2012 Dues are waived.
Click here for the 2012 Membership Application
Central Val ley Chapter - Cal i fornia Land Surveyors Association www.cal i forniacentralval leysurveyors .org
Central Val ley Chapter
PAGE 2 THE PRISM
Classes, training, and continuing education
Editor’s Message
CAD Masters — AutoCAD Level I — Register here July 23, 2012, Sacramento August 6, 2012, Walnut Creek August 20, 2012, Sacramento September 4, 2012, Walnut Creek
CAD Masters — AutoCAD Level II — Register here July 30, 2012, Walnut Creek August 27, 2012, Sacramento September 10, 2012, Walnut Creek
CAD Masters — Civil 3D Introduction — Register here July 30, 2012, Walnut Creek August 13, 2012, Sacramento August 22, 2012, Walnut Creek September 10, 2012, Sacramento
CLSA Webinar — California Prevailing Wage Law September 12, 2012 — Register here
CLSA Webinar — Quality Control for the Land Surveyor October 10, 2012 — Register here
If you have information about a training or class, please submit to: [email protected]
A Worthy Opponent? The results of the April Land Surveying Exams have been released. The National seemed to be held in check with almost half of all applicants passing. The State Specific, on the other hand with the new multiple choice format being put into play, came out swinging. Only 24% of the 384 people taking the test made the passing grade, and that includes the large number of two in the Central Valley. So, with that low a number passing we have to ask, is the test just to difficult or is there just not enough preparation classes available in the area? I think that no matter what your opinion is on this topic, that we can all agree on this, The goal of the test is to make sure that the people being licensed as Land Surveyors in this great State are of the highest quality pos-sible. So with that, maybe we should change the question to, Is the test difficult enough!
If you would like to comment on this topic or suggest another, please submit it to: [email protected]
PAGE 3 THE PRISM
After RTK—Part 1, By Gavin Schrock, PLS Will advances in Precise Point Positioning succeed base-rover and network RTK?
Technology & Info
Continued on page 8
“Always do whatever’s next”—George Carlin Note: this is an expanded version of the article of the same name in the June issue of Professional Surveyor Magazine; the expanded version gave us an opportunity to elaborate on some of the geekier elements of the subject and to add a suggested reading list. The PPP-RTK subject continues in the July print issue in “Taking Cues from the Other Fieldwork,” an examination of the development of PPP-RTK solutions for precision agri-culture and how these developments will likely inform similar solutions for surveying.
Improving on What Is Already Pretty Amazing
No matter how new or amazing a technological tool is that we use while surveying out in the field, our thoughts often turn to the apparent shortcomings of that tool, and we start imagining faster, better, and more cost-effective tools: always setting our sights higher. I’m reminded of the classic Calvin and Hobbes comic where Calvin is reading the instructions on the back of a microwave popcorn packet exclaiming, "It takes 6 minutes to microwave this. Who’s got that kind of time?" GNSS, almost without argument (among those who use it), is one of the most amazing technological developments ever, but is no exception to this dynamic.
Imagine being able to turn on a GNSS rover anywhere in the world and being able to achieve centimeter preci-sions in real-time, without having to set up a base and without having to connect with a network. That scenario is not necessarily on some distant horizon, and a recent symposium on the subject, held in Frankfurt in Febru-ary of 2012, yielded some great insights into just how close were are to those capabilities. The future of high precision real-time GNSS is here, sort of …
Welcome to “GNSS Next,” an ongoing series of articles exploring the next stages in high-precision GNSS, with a specific emphasis on how these developments will serve surveying and related industries. The first few in-stallments will be dedicated to PPP-RTK, what many see as the most-likely viable successor (or complement) to RTK and Network RTK (RTN): current state of the technology, how it works, possible timelines for productiza-tion for surveying use, and some practical and perhaps legal considerations when adopted. GNSS Next install-ments in the print version of PSM will be supplemented with expanded online versions; the online versions like this will include the geekier elements and reference links. Subsequent installments will also look at such sub-jects as constellation upgrades, the impacts of the new signals, jamming mitigation, and communications op-tions for transmission of corrections, other challenges to GNSS, and new GNSS product types and applications on the near horizon.
So, back to the likely successor to RTK/RTN, Precise Point Positioning (PPP) and related approaches like PPP-RTK and States Space Representation (SSR). These ideas are not new—they’ve been available in one form or another almost as long as RTK—but now they’re nearly ready to hit prime time. Some reading suggestions will be referenced throughout this article to a reading list to follow, and as PPP is now moving out of purely aca-demic circles it will soon (most likely) greatly benefit surveying in the near future; it is good idea that we sur-veyors read up on it. A really informative intro into PPP (see Reading List[1]) was put together by Dr. Richard
PAGE 5 THE PRISM
National News Frames for the Future
Continued on page 9
Replacing NAVD 88—Challenges and Benefits (Part 3 of 4): By David H. Minkel and Michael L. Dennis
New Datum Definitions for Modernization of the U.S. National Spatial Reference System
Hybrid Geoid Models-- Applications and Consequences
A transformation tool will be developed by NGS to convert between National Vertical Datum (NVD) and NAVD 88 heights. This tool will be based on the national data set of GPSBMs at the time NVD is released. Con-tinuing to determine accurate and current NAD 83 ellipsoid heights on leveled NAVD 88 bench marks up through the release of NVD will result in a more accurate transformation. This, of course, assumes the bench marks used are still consistent with the overall NAVD 88 network (i.e., the marks have not physically changed in height due to subsidence, uplift, etc.).
As a related note to GEOID09 and future hybrid geoid models, there is significant difference in many parts of the U.S. between GEOID09 and earlier geoid models (see national geoid difference plot in Figure 7). For many areas of the U.S., such as the mountainous western states, it is recommended that previous GNSS sur-veys performed to establish NAVD 88 orthometric control that utilized GEOID03 or earlier hybrid models be evaluated for possible adjustment with GEOID09 (or future hybrid models). In addition to the change in geoid models, NAD 83 (NSRS2007) ellipsoid heights determined in the national readjustment of 2007 also affect GNSS-derived NAVD 88 orthometric heights. GEOID09 is based on the NSRS2007 ellipsoid heights, whereas previous geoid models are based on earlier, more locally determined ellipsoid heights. Recall only NAD 83 (1986) and NAD 83 (NSRS2007) are national realizations; all others were regional realizations. Hence, hybrid geoid models based on regional NAD 83 realizations may have biases due to the local nature of those realiza-tions.
Surveys published by NGS that report GNSS-derived orthometric heights to the nearest centimeter are referred to as "Height Modernization" (HM) surveys. The intent of a Height Modernization survey is to deter-mine NAVD 88 orthometric heights consistent with the local NAVD 88 network, at accuracies of 2 cm or 5 cm (depending on the procedures used, as detailed in Zilkoski et al., 1997 and 2008), without incurring the signifi-cantly higher costs of geodetic leveling. HM surveys determine NAVD 88 orthometric heights on stations by using GNSS observations, a hybrid geoid model, and leveled NAVD 88 orthometric heights on existing bench marks. Observations are performed both on existing NAVD 88 bench marks in addition to new passive stations. In the least-squares vertical adjustment of the survey, constrained ties to existing NAVD 88 control are used to determine NAVD 88 heights on the new stations. As one would expect, if there are significant changes to the hybrid geoid model used in adjusting a HM survey, one might not be able to use control determined in a previ-ous HM survey as constraints in a new HM survey if the surveys used different hybrid models in the vertical adjustments.
As an experiment, four HM surveys previously conducted in Arizona were adjusted with both GEOID03 and GEOID09 and the differences evaluated. In an area of significant difference between the geoid models, us-ing GEOID03-based surveys could not be used as constrained control in surveys performed later and adjusted with GEOID09.
Based on the results of the experiment, the Arizona Height Modernization Program (AZHMP) performed a vertical adjustment of all HM surveys (and other NGS surveys performed to establish precise ellipsoid heights, such as Federal Base Network surveys) with GEOID09. To accomplish this adjustment, 44 surveys (1655 stations) were combined into a single observation file (i.e., a single 1655-station survey spanning from 1996 to 2010 was cre-ated). Results from the combined vertical adjustment shows changes in GNSS-determined orthometric heights
PAGE 6 THE PRISM
State News A Message from CLSA State President, Frank Leamon PLS
This period has had me slowing down a little in my travels compared to the more intense statewide traveling which I had done in the period wrapping up 2011. During those statewide travels, I was able to hear and see many concerns of our profession.
During this past quarter, I had the pleasure of attending the Professional Land Surveyors of Oregon conference in Portland, Oregon at the invitation of the PLSO Board. The conference was well attended as Oregon has a requirement for continuing education, but beyond that, the topics, seminars, and general discussion which came forward were mir-rored a week later by our own joint CLSA/NALS conference in Reno. Lightsquared (LS) and its attempt to modify the use of a frequency originally identified as a low power band adjacent to our GPS frequencies, into a high power terres-trial –read cell phone- frequency, was a topic of discussion in both conferences. I believe that this is not yet put to rest, as LS will most likely not sit quietly on the sidelines and only observe, as they have invested billions of dollars over the past 10 years to get to this point. LS will continue to be on CLSA’s radar for the future.
In talking about the future, it cannot be overlooked that the average age of the survey community is in the 58 to 59 year old range and that we need to bring more people into the profession. At both conferences it was clear that efforts are being made to encourage students to look into, and hopefully join us, in the profession of surveying. Statewide and regional efforts in conducting events and programs such as Trig-star, Twist, Scouting Merit Badge, high school Career Days, as well as the staking of soccer and baseball fields, all reach out to and hopefully plant the seed of interest in today’s youth. We can’t afford to underestimate the impact that a single action that you, as a surveyor, may have on an individual or a group in their thinking of the survey profession as a whole. During a lunch conversation at the Portland conference I had the opportunity to visit with several OIT students and recent graduates who had joined our table. It turns out that one of them had been to Sacramento to sit for the LSIT test and had been treated to the lunch which the local Sacramento CLSA Chapter has been sponsoring. Even though he was a resident of Oregon, and
Continued on page 7
PAGE 7 THE PRISM
A Message from CLSA State President..., cont. from page 6
CLSA Members
receive $20 off
planned to eventually get licensed in both states, he stated that he was convinced he had chosen the right career, and that he was now also going to join CLSA because of that lunch experience. At the same table was Erielle Lamb. We recognized each other from past conferences when, as a student from Fresno, she had helped at the CLSA scholar-ship auctions, as well as having been awarded several scholarships herself. Now having graduated, she had been hired by the State of Oregon and was attending as a PLSO member. I commented that Oregon’s gain was California’s loss, but that she was an asset to the survey profession as a whole. I was encouraged to see these students so in-volved in the profession. The same goes for our own Conference, as many students and recent graduates from Fresno State and other colleges were also in attendance and participated in the various seminars and convention events of-fered. All of these students have benefited from CLSA and the many programs it sponsors. It is, as President, that I would like to task these newest members of the survey community, in particular, to reach out to and use their youth and enthusiasm to spark an interest in the youth of their community. Please get involved in the Career Days of your area and utilize the outreach materials that CLSA has to offer.
In closing, I want to also address a theme that was brought up in both conferences and in several of the seminars that “professional” is not just a title one gets automatically, because it is stated on our registration stamp, or in-cluded in the Business and Professional Code. It is the entirety of who we are, what we do, what we say, how we say it, and how we present and conduct our daily business, ultimately it is earned. One of our speakers commented that, whether we like or not, it is true that we are evaluated and decisions made about us within the first four seconds of an encounter. Keeping in mind that each of us individually represents the profession of surveying, project our Profes-sion the way you wish it to be perceived by the public at large. Often I hear surveyors lament that they are not looked at as a professional such as doctors, engineers, attorneys, and that even realtors are held in more esteem than sur-veyors. Well, perhaps it is time that we think globally about our profession, but act locally in trying to change that perception one contact at a time. Whether that contact is you in a business meeting with a new client, or by your crew in the field when they meet with the client, or the neighbors of the client, you have an opportunity to influence that perception
Reprinted with the permission of California Surveyor Magazine — Spring 2012 Edition
Langley (of the University of New Brunswick and host of the Canspace geodesy forum). Though a bit techie, it is a good starting point to learn about legacy PPP.
Before we examine these concepts and initials, let’s back up to look at the evolution of high-precision GNSS to understand how PPP came about and more importantly why.
Precise Point Positioning in the Evolution of GNSS Single frequency post-processing came about in the years following the launch of the U.S. GPS constellation in 1978. This allowed amazing feats of positioning, even far from civilization and control marks, plus positioning on the seas and in the air. Early commercial receivers began to hit the geodesy and surveying communities for post processing around 1982, followed by early real-time systems like differential services for marine applications. Commercial dual-frequency hit about 1988. Even then, many thought we had reached the pinnacle of GPS capa-bilities, but development did not stand still.
Post processing of the day enabled high precisions, and it still does, widely held as a “gold standard.” Arguably the ultimate in GNSS positioning, post-processing has its own drawbacks for certain applications; it requires temporary or permanent infrastructure (bases or CORS), takes many hours and a lot of skill to do properly—it’s good, but not fast or cheap. Differential real-time of the day required less infrastructure, but it was not very pre-cise—fast, but not good or very cheap. For many applications like surveying and construction, there was a need for higher precision real-time, and in 1992 the first commercial Real-Time Kinematic (RTK) solutions hit the market.
By utilizing dual-frequencies, and differential methods (read up on “double differencing” and “ambiguity fixing”) RTK could yield precisions comparable to that of full post-processing (over short baselines), but in real time. This was good, fast, but not exactly cheap (a base and often someone to watch was needed). A new twist on RTK was added in the late 90s: network RTK (RTN). RTN allowed for longer baselines, not having to set up a base,
geodetic reference, and some other elements could be added (that feature quite prominently in PPP), like im-proved orbit and geodynamic model data. Fast and good, but again, not exactly cheap as there still needed to be infrastructure.
While DGPS was fast enough, good enough, and cheap enough for marine navigation, some agricultural uses, and some mapping uses, it was not good enough for sur-veying. RTK and post-processing is definitely good enough for surveying, fast enough (depending on the ap-plication), and arguably cheap enough.
PAGE 8 THE PRISM
After RTK—Part 1, cont. from page 3
Reprinted with the permission of Professional Surveyor Magazine June 2012 Edition (Click for Complete Article)
PAGE 9 THE PRISM
Replacing NAVD 88...cont from page 5 ranging from -19 cm to +22 cm. In addition, 18 NAVD 88 leveled bench marks that previously could not be con-strained could be used as constraints (presumably because GEOID09 better represents the NAVD 88 datum surface than earlier hybrid models).
In areas similar to Arizona (i.e., where there are significant differences between GEOID03 and GEOID09 as shown in Figure 7), it is likely that HM surveys performed using prior geoid models will not "fit" with later surveys using GEOID09 and NAD 83(NSRS2007) ellipsoid heights, and consequently they will not fit well with the NAVD 88 / NVD transformation tool. However, before undertaking an extensive effort to readjust HM sur-veys in an area to a new hybrid geoid model, some test cases in the area should be investigated. In addition, NGS is in the process of evaluating whether to perform a nationwide vertical adjustment of all appropriate existing GNSS surveys in the NGS database using the latest available hybrid geoid model. Because of this, consultation with NGS is encouraged before undertaking an adjustment of existing HM surveys.
Since NVD is still under development, and NGS is in discussions with Canada and Mexico regarding the new datum, the exact relationship of NVD to NAVD 88 is currently unknown. However, it is a certainty that there will be a significant difference, relative to NAVD 88, in some portions of this country. This is due to the known slope of the NAVD 88 surface compared to the very best continental scale geoid models currently avail-able, which are those from the GRACE (Gravity Recovery and Climate Experiment) satellite mission. As shown in Figure 8, the NAVD 88 datum surface slopes from approximately -1.12 m (below) in the northwest to +0.16 m (above) in the southeast, when compared to GRACE gravity field data. Additional information about GRACE is available at grace.jpl.nasa.gov.
Frames for the Future
Reprinted with the permission of The American Surveyor Magazine, Issue March 2012 Vol.9 No.2
(Click for Complete Article)
PAGE 10 THE PRISM
Classifieds
Have equipment to sell? Looking for a great deal? Check out the CLSA Forums!
If you have a historic or interesting photo you would like to see in a future edition of The Prism, please submit to: [email protected]
Picture of the Issue
Survey Technicians needed in Bakersfield We are currently seeking a Survey Technician II for our Bakersfield office. Responsibilities include taking measurements, performing research, and compiling evidence for boundary determina-tions. Prepares legal land documents and descriptions, mapping and CAD drafting, and assists in performing office and field survey calculations. For a detailed description on job duties, visit www.CannonCorp.us and click on “Careers”. Submit your resume and cover letter on-line at the “Careers” section at www.CannonCorp.us EOE/AA
Or click here to apply
Forest Service Seasonal Hiring Outreach The USDA Forest Service Intermountain Region's Boundary and Title Management Program is currently advertising temporary seasonal (three to six month) employment opportunities for the 2012 field season throughout the region. The openings include Surveying Aids, Surveying Technicians, and Lead Surveying Technicians. Please review the attachment for specifics and how to apply.
HP750C Plus 36” Plotter The I bought this plotter from a local aerial company a couple of years ago. I've used it sometimes 1x per week and some-times daily for a couple of weeks at a time. It works great. If I have problems, then I re-start it (turn it off and on). Once in awhile it wouldn't recognize an ink cartridge, but re-starting eventually fixed the problem.
It won't work with Window 7 (no drivers) but works well with Windows XP. I have the serial cable for it too. It does well with construction color calcs and mono surveys and prints well on Mylar. However, I haven't used it for really nice color plots since the color seems a little off and you can see the lines on large color areas.
I want $350.00 for it. Call me for any questions: 805-845-2133 Eric J Ackerman Gromatici Land Surveying www.gromatici.com (posted on CLSA Classifieds 6-20-2012)
PAGE 11 THE PRISM
Puzzle Page
Across 1. a lineal measurement equal to 16.5 feet 7. Parliamentary ___________ 8. relationship existing be-tween a distance on a map, chart of photograph and the corresponding distance on the Earth 11. our Chapter (2 words)
12. CLSA/NALS Conference held here 13. annual high school mathematics competition based on practical application of Trigonometry 15. lecture held online 16. the science, engineering, and art involved in collecting and managing geographically referenced information 17. CLSA Newsletter of the Year (2 words) 18. “Right of ________” Down 2. chain 3. used for uncovering monuments 4. Imaginary line on ground, all points of which are at the same elevation above of below a specific datum 5. Incoming CLSA President (2 words) 6. Land Surveyor’s tree 9. One square mile 10. science and art of making maps and charts 14. a mark on a permanent object indicating elevation and serving as a reference in topographic surveys
TERMS OF THE PROFESSION 2
Keith W. Spencer, L.S. 6406 Brian Jones, L.S. 7088
CALIFORNIA LAND SURVEYORS ASSOCIATION CENTRAL VALLEY CHAPTER
C/O Stanislaus County Public Works 1716 Morgan Road Modesto, CA 95358
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