Appendix A: Glossary of Terms and Definitions
Acoustic Sensors – A sensor that passively detects and utilizes the presence of sound to locate that sound.
Aerial hyperspectral imaging – Information that is invisible to the human eye, e.g., methane gas leaks, etc. is captured via hyperspectral images.
Ambient Noise Reduction – Active noise control (ANC), also known as noise cancellation (NC), or active noise reduction (ANR), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first which helps isolate specific harmonics when performing certain utility locates.
Artificial Intelligence (AI) – Simulation of human intelligence in machines that are programmed to think like humans and mimic their actions. The term may also be applied to any machine that exhibits traits associated with a human mind such as learning and problem-solving.
Data Visualization – The graphical representation of information and data by using visual elements like charts, graphs and maps.
Augmented Reality (AR) – An interactive experience of a real-world environment where the objects that reside in the real world are enhanced by computer-generated perceptual information, sometimes across multiple sensory modalities, including visual, auditory, haptic, somatosensory and olfactory.
Building Information Modeling (BIM) – BIM software is used to plan, design, construct, operate and maintain buildings and diverse physical infrastructures, such as water, refuse, electricity, gas, communication utilities, roads, railways, bridges, ports and tunnels.
Computer-Aided Design (CAD) – Use of computers (or workstations) to aid in the creation, modification, analysis or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. Designs made through CAD software are helpful in protecting products and inventions when used in patent applications. CAD output is often in the form of electronic files for print, machining or other manufacturing operations. The term CADD (for computer aided design and drafting) is also used.
Cross Bore – An intrusion of an existing underground utility or underground structure by a second utility resulting in direct contact between the transactions of the utilities that compromises the integrity of either the utility or the underground structure.
Digital Camera – A camera that records digital images. Widely adopted in the damage prevention industry to assist in multiple aspects of the business.
Electromagnetic Locating – An electromagnetic locator is used for identifying utilities. They consist of two main parts, a transmitter and a receiver. The transmitter creates a current on the underground conductor that emits an EM field. The receiver detects the electromagnetic field allowing the operator to accurately locate and trace the pipes and cables above ground.
Electronic Positive Response – Communication by telephone, fax, e-mail or internet from a facility owner/operator to an excavator providing the status of an owner/operator’s statutorily required response to a notice of intent to excavate.
Electronic White Lining – The process in which an excavator identifies where proposed excavation will occur by providing a shape on a GIS map; that shape is delivered electronically by the one call center to its member facility operators.
Enhanced Positive Response – See definition of positive response. “Enhanced” means that the excavator receives additional comprehensive information about the site, such as the locate request information, facility maps, photos and virtual manifests.
Geo-fence – A virtual perimeter for a real-world geographic area. A geo-fence could be dynamically generated—as in a radius around a point location—or a geo-fence can be a predefined set of boundaries (such as school zones or neighborhood boundaries). The use of a geofence is called geofencing, and one example of usage involves a location-aware device of a location-based service (LBS) user entering or exiting a geo-fence. This activity could trigger an alert to the device's user as well as messaging to the geo-fence operator. This information, which could contain the location of the device, could be sent to a mobile telephone or an email account.
Geographic Information System (GIS) – A framework for gathering, managing and analyzing data. Rooted in the science of geography, GIS integrates many types of data. It analyzes spatial location and organizes layers of information into visualizations using maps and 3D scenes.
Global Navigation Satellite System (GNSS) – An umbrella term that encompasses all global satellite positioning systems. This includes constellations of satellites orbiting over the earth’s surface and continuously transmitting signals that enable users to determine their position.
Ground Penetrating Radar (GPR) – A geophysical locating method that uses radio waves to capture images below the surface of the ground in a minimally invasive way. The huge advantage of GPR is that it allows crews to pinpoint the location of underground utilities without disturbing the ground.
Global Positioning System (GPS) – A satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Obstacles such as mountains and buildings block the relatively weak GPS signals.
High Dynamic Range Detection – High dynamic range (HDR) is a post-processing method used in imaging and photography for adding more "dynamic range" (ratio of light and dark) in a photograph to mimic what a human eye can see. A classic approach to obtain High Dynamic Range Images (HDRI) consists of combining multiple images of the same scene with varying exposures. However, if the scene is not static during the time of capture, moving objects will appear blurry and ghosted, i.e., in multiple locations. Detecting and removing ghosting artifacts is an important issue for automatic generation of HDRI of dynamic scenes. It also describes locators that can sense strong and weak signals simultaneously.
High Resolution Aerial Imaging – Aerial imagery refers to all imagery taken from an airborne craft which can include drones, balloons or airplane. Adopted by organizations looking to produce their own maps.
Hyperspectral Imaging – A technique that analyzes a wide spectrum of light instead of just assigning primary colors (red, green, blue) to each pixel. The light striking each pixel is broken down into many different spectral bands in order to provide more information on what is imaged.
Internet of Things (IoT) – A system of interrelated computing devices, mechanical and digital machines, objects, animals or people that are provided with unique identifiers (UIDs) and the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.
Light Detection and Ranging (LIDAR) – A method for determining ranges (variable distance) by targeting an object with a laser and measuring the time for the reflected light to return to the receiver. LIDAR can also be used to make digital 3D representations of areas on the earth's surface and ocean bottom due to differences in laser return times, and by varying laser wavelengths. It has terrestrial, airborne and mobile applications.
Machine learning (ML) – The study of computer algorithms that improve automatically through experience and using data.
Positive Response – Communication with the excavator prior to excavation (typically via the one call centers) to ensure that all contacted owner/operators have located their underground facilities and have appropriately marked any potential conflicts within the areas of planned excavation.
Predictive Analytics – The use of data, statistical algorithms and machine learning techniques to identify the likelihood of future outcomes based on historical data. The goal is to go beyond knowing what has happened to provide a best assessment of what will happen in the future.
Radio-Frequency Identification (RFID) – Use of electromagnetic fields to automatically identify and track tags attached to objects. An RFID system consists of a tiny radio transponder, a radio receiver and transmitter.
Real-Time Kinematic (RTK) – Positioning that is based on at least two GPS receivers—a base receiver and one or more rover receivers. The base receiver takes measurements from satellites in view and then broadcasts them, together with its location, to the rover receiver(s). The rover receiver also collects measurements to the satellites in view and processes them with the base station data. The rover then estimates its location relative to the base.
Slot Trenching – Using pressurized air or water to cut a thin and accurate trench.
Simultaneous Localization and Mapping (SLAM) – The process of mapping an area whilst keeping track of the location of the device within that area (sometimes “synchronized” is used in place of “simultaneous”).
Sonde – An instrument probe that actively transmits a radio frequency that is detectable from a locate receiver above the ground. You can insert a sonde into a non-metallic utility such as a clay sewer line and locate the sonde from above the ground multiple times to produce a locate of the entire line.
Subsurface Utility Engineering (SUE) – An engineering process for accurately identifying the quality of underground utility information needed for excavation plans and for acquiring and managing that level of information during the development of a project.
Ticket Screening – A process of filtering, sorting and automating incoming 811 tickets for the facility owner/operator or locator through the use of software rules, algorithms or AI.
Total Stations – An optical surveying instrument that uses electronics to calculate angles and distances.
Thermal Imaging – The technique of using the heat given off by an object to produce an image of it or to locate it.
Tracer Wire – Used to assist in locating non-metallic buried pipe, such as plastic. It is laid alongside the buried pipe and is a conductor of the current that generates the electromagnetic signal that electromagnetic locating techniques search for.
Unmanned Aerial Vehicle (UAV) (also known as a drone or uncrewed aerial vehicle) – An aircraft without a human pilot on board. UAVs are a component of an unmanned aircraft system (UAS), which include a UAV, a ground-based controller and a system of communications between the two.
Vacuum Excavation – A means of soil extraction through vacuum; water or air jet devices are commonly used for breaking the ground.