Merge Your Pipe Location With GIS Technology

Using underground mapping in concert with an electronic locator can give you a leg up on your competition

Merge Your Pipe Location With GIS Technology

Underground pipe has often been a guessing game with GIS mapping systems. Many utilities map from valve to valve, assuming that the pipe between them is straight. Some utilities have imported locations of underground pipe from either as-planned or as-built plans that may or may not be accurate. 

Some underground pipe was field located with older GIS receivers that were not as accurate as today's models. The technology has now advanced so that you can accurately locate pipe location, as well as true depth with a quality locator paired with a high a high end GIS receiver. The two together can log highly accurate actual pipe locations to as high as centimeter accuracy and and pipe depth to within 5 percent. The data can be logged automatically in the field and uploaded to your GIS mapping system. Bluetooth technology allows the GNSS receiver and the pipe locator to communicate and merge data.

Taking your underground mapping to the third dimension

Many utilities with underground pipe and cable have accurate mapping of the latitude and longitude of their underground assets, but not depth. Some have three dimensional maps with surface-level terrain elevations, but still don't have the depth of the pipe or cable below the surface. Adding depth to your GIS data can help your repair crews in planning the depth or size of trench box or other safety gear and planning that may be needed. Knowing depth can help plan the amount of fill required for the repair, or whether a pipe is above or below other utilities in the vicinity. 

Knowing the correct depth can also help identify one type of underground utility from another. A good locator used properly can determine the depth within 5 percent of actual. Therefore a  4-foot-deep water main could be located accurately to +/- 2.5 inches. 

The current technology can also make the job easier by combining the GNSS satellite receiver supplied XY location to the pipe locator Z depth location and logging it in a single file that can be uploaded to your GIS system in several file formats. The logs can also collect attribute data from the locator to confirm the accuracy of the locate including current, mode, and time and date stamps.

Tightening up the accuracy of a GIS system

If you have a GIS map that was not made from true pipe locations, was made with less accurate equipment than you now have or is available, or was made from extrapolated data from locations of surface valve boxes, a GIS-capable locator can help tighten up your system. With a true location of pipe, you can put in bends and curves you may not have recorded, as well as variations in depths going under/over other utilities, stream crossings, or where the surface elevation has changed since installed. Using Bluetooth, we can connect sub-meter, sub-decimeter or sub-centimeter accurate GNSS receivers to a pipe locator for combined data logging.

What works with this technology?

GIS-enabled underground locators work on most any metal pipe or tubing, plastic pipe with line tracer wire and electrical wires and cables. You can also locate sonde transmitters, including those integral to sewer camera heads. Sondes can be inserted on cables into non-pressurized sewer or drainage pipes. It could also be used for plastic water mains where locatable tape was installed or another locatable utility was put in the same trench. In that case, you would be limited to improved XY accuracy, but without true Z depth coordinates.

Mark Beatty is CEO and Principal Owner at Utility Technologies, LLC. This article was originally posted on LinkedIn, and is being used with Mark's permission.


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