The services provided by some of America’s early land surveyors — George Washington, Thomas Jefferson and Abraham Lincoln — obviously were overshadowed by their contributions in later life.
Today there are about 45,000 professional surveyors in the United States, including roughly a dozen in Indiana County.
This week many surveyors around the country will participate in National Surveyors Week activities intended to highlight both surveyors’ contributions throughout history and the new technologies that are influencing the direction of the profession. As part of the observance, surveyors will make presentations to school classes, Scouting groups and other organizations.
[PHOTO: Scott Pilston, left, and Joe O’Donnell, with Environmental Land Surveying & Solutions, set up surveying equipment last week to check a bench mark location at East Pike and Good Drive, at right. (Tom Peel/Gazette photo)]
And some will use their skills and donate some of their time to make the global positioning system more accurate for everyone.
The Pennsylvania Society of Land Surveyors this week will coordinate a GPS data collection project called “Reaching New Heights.”
Explaining the project in surveyor-speak gets pretty technical.
According to the PSLS, the collected data will be submitted to the Online Positioning User Service and the solutions published so the National Geodetic Survey can use them to refine the current geoid to develop the upcoming vertical datum known as Gravity for the Redefinition of the American Vertical Datum.
In layman’s terms, the surveyors and others volunteering their time will use survey-grade instruments receiving signals from GPS satellites to collect and send more accurate elevation measurements for specific points called bench marks.
According to the PSLS, there are many large areas in the state where the accuracy of data for some bench marks is poor. Several bench marks in Indiana County have been classified by the PSLS as “high priority” for improved data.
Brian Buzard, director of operations for Environmental Land Surveying & Solutions in White Township, and a regional coordinator for Reaching New Heights, said some of the bench marks, identified by small monuments or by discs embedded in concrete, were put in place 50 years ago and have since been disturbed by new construction or are now obscured by trees or other vegetation.
Recreation-grade GPS units that cost about $100 can lead a user to within 25 feet or so of where they want to be. But the instruments that will be used by surveyors this week cost about $30,000 and can delivery accuracy within 1 or 2 centimeters, Buzard said.
Surveyors will occupy some of the bench mark sites for 4 1/2 hours to collect and upload the new and more precise elevation data, which, among other applications, will be useful in identifying and managing flood plains.
Frank Lenick, a director of the PSLS, said the work is highly technical but it is also a public service by the surveyors that will benefit society as a whole.
“Everyone uses the data,” Lenick said.