From the Field
April 1, 2007
Many professional surveyors have an appreciation for their early counterparts, but Des Rasch, OLS, takes it to the extreme. Rasch is the founder and owner of Rasch & Chambers Ltd. (www.raschandchambers.ca), a full-service land surveying firm that has operated out of Dunnville, Ontario, Canada, for 28 years with a second office in nearby Fort Erie. He manages Rasch & Chambers with a staff of 10, including two licensed land surveyors.
The area in southern Ontario where Rasch lives and works is a contrast of old and new. The region’s past is visible in the many historical buildings still standing, some dating back hundreds of years. A closer look, however, reveals a modern structure juxtaposed on the bucolic landscape--the Can-Net VRS network, a series of GPS reference stations. Users like Rasch connect to the reference stations via cell phone in the field to receive real-time and post-processed GPS data. Similar to the area in which he works, Rasch also straddles the past and the present in his surveying work.
A Historical HobbyAs both a professional surveyor and an amateur historian, Rasch has extensively researched the history of surveying in his home province of Ontario. He is awed by early surveyors who, in his words, “worked from sunup until sundown, slept around open fires, made crude shelters covered with bark when it rained, were forced to live on meager rations, suffered sickness, serious injuries, and on occasions, even death.” His research into the exploits of early surveyors has inspired him to pose as Augustus Jones, an 18th-century surveyor who played a significant role in surveying various townships in southern Ontario. One of Jones’ accomplishments was running a compass and chain down the center of the frozen Grand River for a survey in the winter of 1791–92.
Rasch’s enthusiasm for surveying is matched by his enthusiasm for the many artifacts he has discovered while out in the field. Some of the native items Rasch has found include projectile points, hammer heads, tools for grinding food and a stone used for spinning sticks to create sparks for fire. He has also found old coins and musket balls, which are possible relics from the War of 1812 and the siege of Fort Erie by American troops in 1814. When he finds a new artifact, Rasch meticulously records the date as well as its location before storing it away.
He also enjoys demonstrating how early surveying instruments work. During the annual Marshville Heritage Festival held each Labor Day weekend in Wainfleet, Ontario, Rasch and other local surveyors set up a historical display with early survey instruments, maps, books and chains. Many of the 35,000 festival attendees stop by the display to view the items, discuss surveying’s past and share their personal stories about an old survey marker or a problem they encountered with their property lines. Children also have an opportunity to try their hand at measuring using an old surveyor’s chain. This coming Labor Day will mark the 16th year that Rasch has participated in the festival. And when the festival ends, Rasch doesn’t put the old surveying instruments in storage. For the last 15 years, he has teamed up with retired surveyor Tony Roberts to give presentations on the history of surveying in Upper Canada to historical societies and United Empire Loyalist groups.
The Conversion to GPSDuring the course of his career, Rasch has embraced many of the technological innovations that have changed the course of the surveying profession. “There are drastic differences in surveying today compared to 28 years ago,” he says. Before he switched to using total stations 20 years ago, Rasch used steel tapes and theodolites as his measuring tools. Ten years ago, he added data collectors to his tool collection, finding that these instruments eliminated errors that occurred when data was manually recorded in the field. Rasch has also come to appreciate data collectors for their capacity to upload and download files. But until three years ago, Rasch had never tried GPS.
If it wasn’t for the influence of a part-time employee at his firm who had worked in surveying all over the country, Rasch might have never tried GPS. His employee argued that surveyors don’t use GPS because they don’t understand how it will help them, and convinced Rasch to take a system for a trial run. The trial proved so successful that Rasch purchased a Trimble (Sunnyvale, Calif.) 5700 GPS base station and Trimble 5800 GPS rover.
Using vehicle-mounted GPS, Rasch can complete a topographical survey of a large parcel of land in a day or less--a feat that would have taken three or four days to complete with a conventional total station. “I’m dazzled by how much topography is picked up using a GPS [receiver] mounted on a vehicle moving twelve to fifteen kilometers an hour,” Rasch says. GPS also allows Rasch to bring accurate geodetic datum to a site very quickly, eliminating hours of effort transferring elevations by conventional means. “Layout on construction sites is made easier with GPS,” Rasch says. “Our firm recently set out roadways, railway lines, ditches and catch basins on a large industrial site for a subcontracting firm. We uploaded the engineering data to the GPS data collector and were then able to easily set out all features on the site.”
Now a firm believer in GPS, Rasch uses the technology for tasks such as laying out new subdivisions, measuring stockpile volumes, and performing boundary surveys of farmland and rural residential lots. “As long as I can see sky, I will use GPS,” Rasch says. Prior to heading to a jobsite, Rasch reviews aerial photographs of the site to determine whether the project requires a one-person GPS crew or a two-person total station crew. Many projects require the use of both total stations and GPS. “We may pick up the evidence away from the immediate property with GPS and use the total station on the actual site,” Rasch explains. “For example, farm surveys in many situations can be eighty percent completed with GPS, and the other twenty percent with total stations. The majority of land on a farm may offer a clear view to the sky, while a bush lot straddles the rear or side line. Using GPS, two or three stations can be set opposite the bush and then traverses with the total station are used to complete the survey of the bush. Transferring between a GPS [receiver] and a total station is easy because the same data collector connects to both instruments.”
A Step AheadNot only has Rasch discovered the benefits of GPS, he has also become a supporter of the Can-Net GPS service provided by his dealer, Cansel Survey Equipment Inc. (www.cansel.ca). Cansel maintains a network of GPS reference stations that provides real-time GPS correction data to users in the field, which eliminates the need for surveyors to set up their own base stations. Using Trimble VRS (Virtual Reference Station) technology, the Can-Net network enables users in the field to connect to the reference stations via cell phone, and receive real-time and post-processed GPS data. The Trimble VRS technology also eliminates or greatly reduces the PPM error in traditional RTK surveying.
One of the Can-Net reference stations in the southern Ontario VRS network is located in Dunnville near Rasch’s office. Dunnville is a rural community situated along the shores of the historic Grand River. Along with its tributaries, the Grand River is the largest watershed in southern Ontario. Because almost 80 percent of the watershed is open farmland and smooth, rolling hills, the topography is ideal for GPS surveying, a feature appreciated by Rasch.
Rasch & Chambers subscribed to the Can-Net VRS network about a year ago, realizing immediate gains in productivity. “I’ve found that Can-Net is easier, quicker and more cost-effective than using a regular GPS with base station and rover,” Rasch says. “Previously, it would take fifteen minutes to set up a base station and another fifteen minutes to take it down, a process that would have to be repeated when moving to a new jobsite the same day.” In addition, Rasch no longer has to worry about leaving equipment unattended. “Our firm has been lucky in regards to theft, but there was always the fear a base station could be stolen when the crew was using the rover a few kilometers away.” After subscribing to Can-Net, Rasch no longer needed his own base station and converted the Trimble 5700 base station into a second rover, effectively doubling his survey crew access to GPS. With two crews now outfitted with GPS and having access to the Can-Net VRS network, Rasch is thinking about adding GPS to his third crew.
With one foot in the present and one in the past, Des Rasch seems comfortable in both worlds.