Surveying and GIS: Finding the missing link

The Value of Land Surveyors

Ten years ago the California Board for Professional Engineers and Land Surveyors (BPELS) attempted to pass a set of rules that required all digital mapping to be performed by Professional Land Surveyors. The motivation for these rules stemmed from the definition of surveying under the California Professional Land Surveyors’ Act, which includes specific reference to digital mapping being within the purview of the Professional Land Surveyor. The BPELS at the time concluded that there were sufficient risks in the making of digital maps, which if made incorrectly, could cause damage to the health and welfare of the public.

The BPELS is made up of 13 members. Seven of these are public members (having no professional background in Engineering or Surveying), five are licensed Professional Engineers, and one is a licensed Professional Land Surveyor. The following history of the BPELS appears on their web site:

A Brief History of the Board

The California Legislature created the Board of Registration for Civil Engineers in 1929, following the failure of the St. Francis Dam in northern Los Angeles County. On March 12, 1928, the dam, which was located northeast of Castaic, suddenly gave way. A huge wall of water cascaded down the narrow valley of the Santa Clara River and when the water hit the town of Santa Paula, almost 50 miles downstream, the crest was still 25 feet high. The dam failure unleashed 12 billion gallons of water through the towns of Piru, Fillmore, Santa Paula, and Ventura before it reached the ocean. Lives lost numbered approximately 450; property damage was in the millions of dollars; 1,200 houses were demolished; and 10 bridges washed out. After the flood, inspection revealed that the dam was built on, and anchored to, a weak and faulted rock formation. The Legislature determined that the unregulated design of construction projects constituted a hazard to the public and passed laws to regulate civil engineering and to create the Board.

Although Civil Engineers first became licensed in 1929, Land Surveyors have been licensed in California since 1891. That was the year the Legislature established the State Surveyor General. However, in 1933, the Legislature abolished that office and enacted the Professional Land Surveyors’ Act. The Act expanded the Board’s authority to include jurisdiction over licensing of land surveyors and regulation of surveying practices. …Regulation of land surveyors brought about uniform enforcement of survey law and is in the best interests of the state and California consumers. (from http://www. pels.ca.gov/about_us/history.shtml)

The history of BPELS highlights the need for society to regulate professional practice and to maintain a minimum set of standards in order to protect the information from recorded documents, statutes, case law, and measured evidence found in the field to arrive at the true location of legal title boundaries to real estate. In this text Mr. Gold cites approximately 550 precedent setting court cases specific to Texas that have added to the body of knowledge of how professional land surveyors should treat conflicting evidence describing the location of boundaries to real estate. A similar body of court cases is slowly mounting covering mapping and GIS products.

Location on or near the Surface of the Earth

Of course, the surveyor is also adept and skilled in the science of measurements to determine relative location (say property corners within a subdivision) and absolute location (say relative to the national mapping grid). Throughout the history of land surveying, the science of locating position on the surface of the Earth and the measurement of the size and shape of the Earth (Geodesy) is well documented and resides within the domain of the Surveyor and a specialist surveyor, known as the Geodesist. One of the first texts on surveying in English, Geodaesia by John Love, was published in 1688 in London. The text describes the reduction of field measurements of angles and distances by compass and chain, then using logarithmic and trigonometric tables to compute boundary locations.

The ancient analogue measuring instruments used in 1688 have been replaced by digital measuring systems, including GPS, digital theodolites (total stations) with built-in electronic distance measurement, and digital levels using bar code reading systems. All these measurements are data logged and imported into surveying software and digital drafting software. The end products of these digital surveys are easily imported into GIS software. Much of the surveyor’s time in both the field and in front of the computer is spent on making redundant checks. These built in checks are essential for the computation of accuracy and precision using statistical evaluation software. When results lie outside given tolerances, field measurements are repeated until the required standards are met.

Most surveyors have exposure to GIS with some actively using GIS to manage their own geospatial data. GIS software vendors are also making life easier for surveyors to use GIS by incorporating surveying functionality within GIS (a good examples is ESRI’s ArcSurvey). Recent surveying graduates are well versed in GIS with many university programs incorporating courses in GIS as part of the surveying degree curriculum (for example see http://csci.tamucc. edu/gisc/). Why is it then that most GIS enterprises do not involve surveyors?

From background noise’to one of ‘raised consciousness Jack’s comments are interesting, although I would tend to disagree with his assessment on the current nature of the ‘tension’. Perhaps it’s just semantics, but I personally believe that the ‘tension’ is not so much growing as it is ‘maturing.’ For example, the MAPPS lawsuit has ostensibly raised the tension level, but I wonder if it just moved the issue from being one of ‘background noise’ to one of ‘raised consciousness’. As I speak around the country, which I do on a regular basis, I think I detect more interest and more collaboration between the Surveying and GIS communities than in the past. Gary R Kent PLS, Integrated Services Director, The Schneider Corporation

The Shrinking Surveying Profession

Throughout the developed world there is evidence that the total population of qualified and licensed surveyors is diminishing. A similar trend is also happening in the Engineering professions. There has been an explosion of career opportunities brought about by the rapid advance of computing power, which has widened the career horizons of potential young professionals who have a liking for mathematics, physics, and computer science. Surveying also has the handicap of having a very low public profile. The general public very rarely needs the services of a land surveyor. Surveyors provide their products and services to other professionals (engineers, architects, lawyers, government administrators, and land developers).

As a consequence of the few people choosing to seek careers in surveying, the profession is generally growing older. The following graph and tables show the age profile of Registered Professional Land Surveyors in Texas. Some interesting trends can be seen from these numbers:

• The number of surveyors in Texas over the past five years has remained flat while the state has one of the fastest growing populations in the U.S. and demand for surveying services continues to grow.

• There are more active licensed surveyors over the age of 70 than there are under the age of 40.

• Fully 20 percent of surveyors in Texas are of retirement age (65 years or older).

These numbers also indicate that while surveyors are declining in numbers relative to the general population, they are keeping up with overall demand for services thanks to those surveyors that choose to remain in the workforce beyond retirement age. Surveyors are also taking advantage of new digital surveying measurement equipment and software to increase productivity. It follows that the cost of surveying services are being driven higher and the demand for educated and licensed surveyors is being reflected in higher salaries being offered.

Accuracy and consistency of GIS database is very important The differences among the Surveying and GIS community largely stem from alternative academic approaches to the subject. It is well understood that it is the quality of information that matters most in a GIS database. Top level decisions are being made based upon GIS databases. Any inaccuracy or inconsistency in those databases may result in serious repercussions. Hence, the accuracy and consistency of GIS databases are of vital importance. In such a scenario, certification of the GIS database may become an issue. Professionals who are trained in database generation definitely have a significant role to play. Surveyors are the most competent professionals to provide and analyze the quality of spatial information. But if it is insisted that only surveyors have the rights to do so, then I think the argument is taken too far. If professionals from the GIS community are capable of providing spatial information and analyzing it to the required quality, then why not? The differences between the Surveying and GIS community also reflect the conflicts of professional interests. However, there is a definite need to reduce these differences. Matthew Smith Leica Geosystems

Adding GIS to the Duties of the Surveyor

The land surveying profession has the expertise to assist the GIS industry manage the risks associated with accuracy and precision of geospatial data. Surveyors have a rich history of understanding the science behind measuring the location of objects on or near the surface of the earth and turning these measurements into legally admissible products and documents recognized by government and the courts. While many GIS products and services may not carry much risk, its value rising.

Young surveying professionals do have educated backgrounds, which include GIS, and are entering careers that see their services benefit GIS products. However, their number is very low. With the median age of surveyors being in the latter fifties, and many already being over the retirement age, we see the majority of the surveying profession in the latter stage of their careers and probably not interested in taking on the extra work associated with the growth of the GIS industry. In many areas there is more than enough traditional surveying services demand keeping surveyors gainfully employed.

While state boards, like BPELS, are concerned with protecting the public against the risk associated with geospatial data and information emanating from GIS, there seem to be few surveyors that have the desire to take on these extra duties; if mandated by board rules. There still needs to be more dialogue between the GIS industry and the surveying profession so each group better understands how cooperation can benefit all parties, including our clients. Though BPELS withdrew the proposed rules to make licensed surveyors responsible for the quality of GIS digital mapping products, the proposed rules did spark the dialogue between surveyors and the GIS industry. Ten years since BPELS proposed their controversial rules, we see the numbers of surveyors are less, while the GIS industry continues to grow. The more we learn and discuss these issues, the better we will be prepared for serving our clients in the future.

Accuracy and consistency of GIS database is very important There is an opportunity for convergence of the survey market and GIS. Surveyors create maps for record plats and for as-builts used by civil engineers, and surveyors stake out projects for construction purposes using maps provided by engineers and architects. These maps have typically been prepared in either MicroStation or AutoCAD format. The GIS world has been dominated by the ESRI platform, which also can present maps accurately. The capabilities of these platforms in presenting 2D and 3D data have largely converged, but no single survey application solution has linked the user interface across all 3 platforms (ESRI, MicroStation and AutoCAD). Once this occurs, surveyors can choose to work in the platform of their choice and specifically can take advantage of the data links offered by the ESRI platform. Given the prevalence of ESRI in the government sector, and the fact that both survey platting and utility and infrastructure mapping is a data-rich environment, it is inevitable that surveyors will begin to consider ESRI as a mapping platform once familiar survey solutions are provided on the ESRI product base. Bruce Carlson, President and Founder of Carlson Software