Glossary
The terms, defined plainly.
What the words on this site mean, in the order a crew meets them.
- Pre-dig verification
- The final check a crew makes at the exact dig point, right before breaking ground, to confirm what is below. It comes after 811 marks and any survey, and it leaves a record.
- 811 / One Call
- The free notification service excavators must contact before digging. Member utility owners then mark their lines with paint and flags. Required notice is usually two to three working days.
- APWA color code
- The uniform colors for utility marks: red electric, yellow gas and oil, orange communications, blue potable water, purple reclaimed water, green sewer and drain, pink survey marks, white proposed excavation.
- Ground penetrating radar (GPR)
- A radar that sends pulses into the ground and reads the reflections from changes in material. It finds metal and non-metal targets, including plastic, clay and concrete-encased pipe.
- Fully polarimetric GPR
- A radar that transmits and receives in two polarizations at once, so a buried line is detected whichever direction it runs and can be told apart from rocks and clutter.
- Progressive scanning
- Scan, dig what the scan cleared, scan again from inside the trench. Each pass clears the next layer before the bucket takes it, so soil no longer limits depth.
- Trench mode
- The GSX1000 configuration for scanning inside a trench or auger hole: the radar core lifts out of its sled and the handle plugs into the top of the housing. Fits openings from 18 inches.
- Dig / no-dig
- The plain-language result a verification scan gives the crew: clear to dig here, or there is a target under this spot.
- Detection
- A target the radar found and the software reported, with its position on the map.
- Damage-prevention record
- The stored proof that a check was made: the scan's position, date and time, operator and unit, job, and detections. In GroundScope every scan becomes one automatically.
- Subsurface utility engineering (SUE)
- An engineering practice that maps utilities to defined quality levels for design. Detailed and valuable, but a snapshot of the day it was done.
- Utility strike
- Contact with a buried line during excavation. In the United States one occurs every few minutes; the costs include repair, downtime, injury and liability.
- GPS-RTK
- Real-time kinematic GPS, which corrects satellite positioning to a few centimeters. With an inertial unit and factor graph filtering, the GSX1000 places each scan to about 3 cm.
- IP65 / IP67
- Ingress protection ratings. IP65: sealed against dust and water jets (the GSX1000 housing). IP67: sealed against dust and immersion (the command tablet).