John Houston is at work on Gough Island, a British territory 2,700 kilometers (1,700 miles) west of Cape Town, South Africa. He is neither a surveyor nor a heavy traveler. So what is he doing on a speck of an island, knee deep in brush and muck while operating a high-accuracy GNSS receiver?
It’s all about the birds.
The tiny landmass of Gough Island covers just 91 square kilometers (35 square miles) and is regarded as one of the Earth’s least disrupted ecosystems. It is home to indigenous birds and invertebrates. Unfortunately, the birds are in trouble.
While Gough Island has no native mammals, it has plenty of mice, which consume roughly two million defenseless eggs and chicks each year. At this rate of loss, the birds face extinction.
To protect the birds, the RSPB initiated a project to eradicate the mice. Houston was there to help.
A trained engineer, Houston would support the RSPB efforts by gathering topographic and geotechnical information, including mapping with GNSS. But even advanced GNSS has limitations, especially in such a remote location. Faced with strict requirements for accuracy, Houston turned to Trimble CenterPoint® RTX positioning service, which enabled him to conduct precise GNSS measurements in the challenging environment.
Houston’s job was to collect information for use in planning temporary facilities that would support the eradication. He needed accurate information on the terrain. Adding a surveyor to the team was costly so Houston performed double duty by handling surveying and engineering. With only two weeks to complete his work, RTK GNSS seemed to be an ideal solution. But Houston’s lack of survey experience and the absence of cellular service made RTK unfeasible.
To simplify his task, Houston used a Trimble® R10 GNSS receiver and Trimble CenterPoint RTX correction service, which uses a global network of GNSS reference stations and satellite communications to achieve real-time, centimeter-level positioning accuracy anywhere in the world. With the R10—and a Trimble TSC3 controller and Trimble Access™ field software—Houston collected hundreds of 3D points around the project site. “The weather and terrain made life miserable,” Houston recalled.
Even as a self-described “rookie surveyor,” Houston quickly learned to operate the GNSS equipment. With CenterPoint RTX operating transparently, he could focus on the engineering tasks. The R10 was the only survey tool Houston needed.
Houston departed the island with sufficient data for the design work. He developed 2D contour maps and 3D terrain models of the site, which were shared with RSPB. The society will overlay bird data on the topographic maps to identify flight paths and nesting areas.
CenterPoint RTX was invaluable for the success of the project, he said, and though it was a long journey and rugged conditions, the opportunity to see and interact with the birds left a lasting mark. “It was a once in a lifetime experience,” he said.