Transmission corridors and vegetation management

Transmission corridors and vegetation management

What utilities and their vegetation contractors fly over transmission corridors, the rules that set the pace of that work, and what Omniris does with the data: LiDAR processed into vegetation-to-conductor clearance, clearance points turned into tracked work items, thermal and photo inspection, and a tamper-evident record of when each span was inspected, and what was found.

Summary

A tree growing into, or falling onto, a high-voltage line can start an outage that spreads across the grid, which is why vegetation along transmission lines is one of the most closely regulated parts of utility work. In North America, NERC Reliability Standard FAC-003-5 requires owners of covered lines to keep vegetation out of a minimum clearance distance, inspect 100% of those lines every calendar year with no more than 18 months between inspections, finish an annual work plan, and keep the evidence for three years.[1] In California, state clearance rules and wildfire mitigation plans add more inspections on top.[5][7]

Utilities now meet those obligations with aerial LiDAR, drone structure inspections and thermal patrols, flown by their own pilots, by contractors, or both.[5][8][9][10] The hard part is rarely the flight. It is turning gigabytes of points and thousands of photos into a short list of places a crew must go, and proving later what was seen, when, and what was done about it.

Omniris covers that path from the data to the work item and the record:

How utilities use drones on transmission corridors

A transmission programme has two jobs that drones now serve: keeping vegetation out of the lines, and keeping the lines themselves (structures, insulators, hardware, conductors) in repair. Both are driven by rules with fixed cycles and by a growing expectation that the utility can show its work.

The rules that set the work

How close is too close

The MVCD values in FAC-003-5 are flash-over distances calculated with the Gallet equation, with the gap factor set from EPRI test data; they vary with voltage and rise with altitude. A few rows of its Table 2, for lines from sea level up to 500 ft (152 m) elevation, with the metre values from the standard's own metric table:[1]

These are the distances that must never be crossed under any rated operating condition. Utility trim distances are larger, because vegetation keeps growing and conductors move. PG&E's transmission standard, for example, sets its own minimum clearance distances of 4 ft (1.2 m) for 60/70 kV lines, 10 ft (3.0 m) for 115 kV and 230 kV lines, and 15 ft (4.6 m) for 500 kV lines, stating that they "meet or exceed" both FAC-003-5 and GO 95.[5] That is why clearance bands in an inspection tool need to be settable, and why a number on a screen is not the same thing as a compliance determination.

The missions

PG&E's transmission vegetation standard shows how these fit together. Its annual patrol "uses light detection and ranging (LiDAR) technology to identify potential tree risk"; ground patrols "are informed by the LiDAR detections"; the tree-work population comes from the LiDAR analysis plus the ground patrol; and NERC tree work must be complete by December 31. A second patrol covers High Fire-Threat Districts. LiDAR is flown by contract partners whose job is "to identify vegetation in proximity to Transmission overhead assets", and the utility's own inspectors prescribe the work.[5]

LiDAR or photographs?

For vegetation clearance, LiDAR is the usual sensor. A peer-reviewed review of drone LiDAR for utility vegetation management cites studies in which LiDAR outperformed photogrammetry for locating vegetation and estimating tree height, and in which photo-based (structure-from-motion) models were less accurate than LiDAR at mapping the terrain under canopy, because LiDAR records several returns per pulse and reaches the ground through gaps in the trees.[11] Structure and component condition is still recorded mainly in photographs: a fixed sequence of close-up and zoomed images of each structure, plus thermal.[8]

Who flies

Models vary. Southern Company runs a hybrid: vetted contractors, a corporate aviation team of full-time drone pilots, and employees trained to fly for their own business needs, more than 200 remote pilots in all.[9] Its Georgia Power unit's structure-inspection programme started with transmission specialists who were also trained drone pilots.[8] System-wide LiDAR is often bought as a service: PG&E's LiDAR is flown by contract partners, and its own inspectors prescribe the work.[5] Helicopters are still in use: FirstEnergy's 2024 transmission vegetation inspections used helicopters carrying LiDAR.[10]

What it costs and what it replaces

Drones against ground crews (structures). In Georgia Power's comparison, drone inspections found more abnormal conditions than ground crews, and the utility estimated it could save about 60% a year with drone inspections (utility-reported in trade press).[8]

Where it still hurts

• The lines below 200 kV. In ReliabilityFirst's region, 290 of 309 vegetation-caused transmission outages from 2021 to 2024 (95%) were on 100–199 kV lines, a class largely outside FAC-003's scope, with lower towers and narrower rights-of-way, and the number has risen since 2022.[3] In a May 1, 2026 report to FERC on wildfire risk, NERC recommended revising FAC-003-5 to apply to more transmission facilities between 100 kV and 200 kV, through its standards development process.[18]
• Inspection plans that fall short. ReliabilityFirst reports that the most common root cause of recent FAC-003 violations was the vegetation management plan itself: too long between inspections, inspections when foliage was not visible, inspections from too far away, lines left off the clearing schedule, and weak oversight of the vendors doing the work.[2]
• From data to a crew. LiDAR detections still have to be field-verified and turned into work: at PG&E, ground patrols follow the LiDAR detections, the tree-work population comes from both, and NERC tree work must be complete by December 31 of each year.[5]
• Sag and sway. Rules are written for any conductor position under rated conditions;[1][6] a flight sees one position. Line-design models of maximum sag remain a separate step.
• Proving it. Inspection dates, findings and completed work have to be shown to an auditor three years later.[1]
• Line of sight. Long linear inspections are the case the FAA's proposed Part 108 rule on flights beyond visual line of sight is meant to open up. It was proposed on August 7, 2025, explicitly listing "aerial surveying" and inspection of "energy production, transmission, and storage infrastructure", and the final rule went to White House review on July 10, 2026.[14][15] Until a final rule is published and in effect, flying beyond visual line of sight in the United States needs a waiver, which some utilities hold.[9]

Use case by use case: what Omniris does

Omniris is a processing platform and evidence vault, with a marketplace for hiring pilots. For each transmission use case, this is what it delivers.

Vegetation clearance from LiDAR

Upload the survey's LAS or LAZ files to a folder (one file or a set of tiles from any scanner or provider) and choose Process LiDAR. Before anything is charged, the dialog reads each file's header and shows the number of points, the coordinate system and the price; files in different coordinate systems, or with no coordinate system stated, are caught here rather than half-way through. Tick Measure clearance between vegetation and overhead lines and set the two distances. The defaults are critical under 10 ft (3.0 m) and clear from 15 ft (4.6 m), with warning between; set them to your own trim distances for the line.

The job labels every point with a standard LiDAR class (ground; low, medium and high vegetation; building; wire; tower; noise), works out its height above the ground, and builds a terrain model (DTM), surface model (DSM), canopy height model and contours. If the provider already marked the ground, that work is used. Then, for clearance:

Results appear three ways: the point cloud coloured by band in the 3D viewer, a list of clearance points worst-first (select one and the view flies to it), and a results file with each point's location for GIS. The point cloud streams into a browser tab, so a reviewer needs no LiDAR software, and a ruler measures between any two points in feet or metres. The LiDAR and point clouds paper describes the processing, viewer and classes in full.

Illustrative example values.

Correcting the classification

Automatic classification can be wrong: a stretch of conductor missed, a guy wire picked up as a wire, a dense flat-topped hedge taken for a building, low brush taken for ground. The classification editor works inside the same 3D viewer, with rectangle, lasso, polygon, box, brush and line selections and a side-on section view, filtered by class or height. Edits are a saved draft with undo and redo. Apply writes them into a new version of the point cloud beside the original, which is never changed, and the job reports exactly how many points moved between classes. Regenerate then rebuilds the terrain models and the clearance check from the corrected classes; until you do, clearance on an edited version is marked as measured before the edit.

From clearance point to finding

A list of distances is not yet work. In the LiDAR dialog, tick Create findings for the clearance points automatically, and when the job finishes each clearance point becomes a finding: a work item on the map titled like "Critical: vegetation 3.9 ft (1.2 m) from conductor", filed under Vegetation encroachment. By default a warning-band point is High severity and a critical-band point is Critical; your organization can change those rules. Or promote from the results: one point, Promote all critical, or Promote all.

• Filed once. A clearance point that falls on an open finding of the same kind is added to it as new evidence instead of opening a second finding, so next year's survey of the same span adds to this year's work item if it is still open. Resolved and dismissed findings are never reopened by a new sighting.
• Worked to closure. Each finding has a status (by default New, Confirmed, In progress, Resolved, False positive, Duplicate), an assignee who is emailed, comments, evidence photos and a full history. A version made by Apply or Regenerate keeps the original job's choice to create findings.
• In the field. The Omniris phone app lists the findings assigned to you, navigates to each, and lets the inspector change the status, comment and add photos, with or without signal; the 25 most recently updated open findings assigned to you are kept on the phone.

Structures and components

Structure photos from a drone inspection go into the vault with their positions, where anyone permitted can review them in the image viewer. An inspector can draw a finding directly on a photo as a pin or an outline; Omniris traces it from the camera's position and angle onto the ground and records how precisely the place is known. AI detection lets you type what to look for in plain words and run it over a folder of photos or a map; every result is a first draft that a person checks, corrects and marks Verified, with the check sealed in the image's custody record, and detections can be turned into findings. An orbit flight around a tower can be built into a 3D model, with findings placed by clicking its surface.

Each finding belongs to a folder and a site. Put the structure number in a finding's title or description and the findings list finds it by that number.

Thermal patrols

Thermal photos from DJI and FLIR radiometric cameras are converted to real surface temperatures and stitched into a temperature map, labelled THERMAL only after its values are checked. On it you can click for a temperature, compare two readings and grade the difference (ΔT) vs similar component (four grades) or vs ambient (five grades) on scales that follow common electrical-inspection practice, highlight everything above a temperature, and run hot-spot detection. A line corridor uses the general settings: areas at least 10 °F (5.6 °C) above the flight's typical temperature and at least 10 ft² (0.9 m²), adjustable and re-runnable. Hot spots can be promoted to findings, or created as findings automatically; the starting severity rules never mark a thermal finding Critical, and your organization can change them. See the Thermal Imaging paper.

Right-of-way encroachment and change

A new shed, a parked trailer or dumped material in the right-of-way is a different problem from a tree. Two Omniris tools help. AI detection finds what you name on a stitched map or in photos. AI change compares two dated maps of the same site that were analysed with the same AI model and wording, lists every object that appeared or disappeared, and files each one as a finding with a side-by-side image of both dates. In LiDAR, buildings are labelled as their own class, but the clearance check measures from vegetation only, not from structures.

Storms and damage

After a storm, photos from any drone can be uploaded, stitched into a map or built into a 3D model, searched with AI detection, and turned into findings for restoration crews, then shared by link with a password and expiry date. The same custody record covers the imagery, which matters when damage becomes an insurance or cost-recovery claim.

Asking Orion

Orion, the Omniris assistant, can answer questions about your LiDAR jobs and findings from the same records the screens use: which corridors have been processed, how many clearance points a job found and how many were critical, the closest distance found (in feet first), and which findings are still open. It treats a "not assessed" result as not assessed, never as clear, and it sees only what the person asking is allowed to see.

Accuracy, clearance and standards

Omniris does not publish an accuracy figure for its classification or clearance, and this paper does not quote one. A clearance distance is only as good as the survey behind it: the scanner, the point density, how well each wire was hit and how the survey was georeferenced belong to whoever flew it. What Omniris does is state, on every result, what was measured and what was not.

What a clearance result means

• As flown. The distance is between the vegetation and the wire where both were at the moment of capture. Sag at maximum load or temperature, wind blow-out and growth until the next trim are not modelled. FAC-003-5 and California's PRC 4293 are written for any conductor position under rated conditions, so an as-flown distance is an input to that assessment, not the assessment.[1][6]
• Your distances, not the standard's. Omniris does not know a line's voltage or elevation and does not look up an MVCD. You set the critical and clear distances, in feet, for each job. Set them to your trim specification, which is normally well outside the MVCD.
• Detected wires only. The check measures to the wires the classifier found, about 10 ft (3 m) or more above the ground. It does not know which circuit or phase a wire belongs to, and anything long, thin and hanging in the air, including a communications cable or a guy wire, may be treated as a wire unless you correct it.
• Not assessed is not clear. With no wire detected there are no bands at all, and the result says so.
• Every result carries the statement "Not a compliance determination", in the results view and in the clearance file, and Orion never describes a clearance result as a compliance determination.

Coordinates and heights

• Any common map grid. State plane in feet, UTM, national grids, or latitude and longitude. Results stay on the survey's own projection, converted to metres (a survey in latitude and longitude, or in web map coordinates, is placed on its UTM zone, on the same datum); feet are a display choice. A file that does not say which coordinate system it uses is not guessed: you are asked for its EPSG code.
• The height reference is carried, not changed. If the file states its vertical reference (NAVD88, for example), the results say the same; you can state one the file lacks, and that is recorded as yours. Heights are never converted to another reference. Clearance is a distance within one survey, so the vertical reference does not change it.
• NAVD88 surveys stand alone in 3D. A LiDAR survey can be shown over a 3D model from another flight only when both height references are known and can be related (ellipsoid and EGM96 mean sea level can). A survey whose heights are above NAVD88 is viewed and processed on its own.

Standards Omniris works with

Evidence and records

FAC-003-5 names the evidence an auditor will ask for: dated attestations, dated work orders, invoices, or "dated inspection records", kept for three calendar years.[1] A wildfire investigation or a damage claim can reach further back and ask harder questions: what did the utility know about this span, and when? Omniris keeps the survey, the results and the work items in one vault under one tamper-evident custody record.

• Every file has a custody history. Uploads, views, downloads, shares, processing results, encryption and deletion are sealed into a record that can only be added to. Every hour the new events are combined, signed with the deployment's key and timestamped by an independent authority (RFC 3161), so no event can later be altered, removed or back-dated without it showing.
• Survey and results are linked. The classified point cloud, terrain models and clearance file are recorded as outputs of the job that made them, from the files it read; a corrected version records which point cloud it came from and who applied the edits.
• Every change to a finding is sealed. Creating, assigning, status changes, comments, evidence, deletion and restoration are recorded with who did it: a person, an automatic run or an API key.
• Certificates anyone can check. A signed PDF custody certificate for a file, or a finding certificate listing a finding's complete history and its evidence fingerprints, can be checked online or entirely offline with free tools, without relying on Omniris.
• Legal holds and retention. A hold on a folder, job or site freezes the survey, results and findings together; a retention policy can keep records for the period your programme requires, then dispose of them with a signed certificate. Results under a hold are never replaced by a re-run: the new run is refused before it starts.
• Encryption. Surveys in an encrypted folder can be processed, and their results and evidence images are encrypted as they arrive.

Omniris gives your compliance staff dated, verifiable records from which to build the FAC-003 evidence package; the attestation itself remains theirs.

Getting the flights flown

Utilities fly with their own pilots, with contractors, or both. Omniris works either way: in-house teams use it as their processing platform and vault, and the marketplace in the cloud and data center editions connects a utility or vegetation contractor with independent pilots.

Hiring pilots through the marketplace

• A job request with the corridor drawn on it. Draw one or more areas on a satellite map, set dates, deliverables, site conditions and insurance requirements, and publish. Every job carries an Airspace card showing the FAA airspace over it.
• Pilots who can take it. Pilots see open jobs within their travel radius and apply. A pilot's Part 107 remote pilot certificate is checked against the FAA's airmen registry, and the job-readiness panel tells pilots what still stands between them and applying (certificate, equipment, a verified address, account approval). You can also offer a job directly to a pilot you choose.
• On a cycle. A recurring job repeats weekly, every two weeks, monthly, quarterly or every N days, weeks or months (every 12 months, for an annual patrol). Each occurrence is its own job with its own flight window and delivery folder, and you are emailed as each one is created.
• Delivered into your vault. The pilot delivers results straight into your vault, where you accept them or send them back, with the custody record running from the first upload.

Marketplace, payments and payouts are part of the cloud and data center editions only; on-premises installations have no commerce.

In-house crews

An organization has one shared vault, with managers, pilots and viewers. A job can be assigned to one pilot or to the whole organization, so a team can work a corridor together and a manager submits the results. Pilots can also log work they arranged themselves.

Planning the flight

The mission planner builds photo flights from the areas drawn on a job or site:

• Corridor. Parallel lines along a drawn line route, at least two of them so the photos can be stitched, with heavy front overlap by default (85% front, 70% side, camera straight down). Give a width and the planner adds the lines it needs.
• Orbit and perimeter for towers and structures, for 3D models.
• Terrain follow from a worldwide terrain model or your own earlier survey, so the drone holds its height above the ground along a ridge line.
• No-fly zones and airspace. Zones drawn on a job are flown around with a margin; the whole route is checked against FAA airspace, and where LAANC authorization is needed Omniris works out what to file and keeps a record of what was granted. A Part 107 pre-flight checklist is saved with the job.
• Exports for DJI Pilot 2, DJI Fly, Litchi and QGroundControl, or a boundary and parameter sheet for apps that plan their own lines.

The planner builds camera flights. LiDAR surveys are flown with the aircraft maker's own planning app and turned into LAS or LAZ point clouds by the maker's or provider's software; Omniris takes over from those files. The planner warns above 400 ft (121.9 m). Keeping a flight within visual line of sight, or holding a waiver for one beyond it (and under Part 108 a permit or certificate once a final rule is in effect), is the operator's responsibility.[14][15]

Integrations and delivery

Utilities run work through enterprise asset and work-management systems such as IBM Maximo, SAP or ServiceNow. Omniris provides the standard pieces your integration team, or a systems integrator, connects to them in their usual way:

Cloud, data center and on-premises

Omniris runs as a cloud service on Microsoft Azure or Google Cloud, as the Omniris data center edition, or on-premises on your own hardware. LiDAR processing, the classification editor, clearance, findings, thermal tools and the custody record are the same in every one.

A selection larger than one job's limit is refused before it starts, with the limit stated, so a long corridor is processed as several jobs of fewer tiles. LiDAR processing needs no graphics card. For a utility that keeps grid data inside its own network, the on-premises edition keeps surveys, results, findings and the custody record on its own hardware; webhooks can be allowed to named addresses on the site's own network. The marketplace and payments are not part of on-premises installations.

What a result claims, and what it doesn't

Clearance and inspection results feed safety and compliance decisions, so Omniris states what they are:

• A clearance result is not a compliance determination. It is not a finding of compliance or non-compliance with FAC-003, GO 95, PRC 4293 or any other standard, and Omniris does not produce compliance reports or attestations. A processed survey is not a licensed land survey.
• Distances are as flown. Conductor sag at maximum load or temperature, wind blow-out and vegetation growth are not modelled; maximum-sag analysis needs line-design software and the line's design data.
• The bands are your distances. Omniris does not know a line's voltage or elevation and does not apply MVCD values; the critical and clear distances are the ones you set for each job.
• Measured to the wires it detects. Clearance is measured to wires the classifier found, about 10 ft (3 m) or more above the ground. A conductor the survey captured poorly may be missed, a communications cable or guy wire may be treated as a wire unless corrected, and with no wire detected the result is "not assessed", never "clear".
• Grow-in, not fall-in. Vegetation within at least 49 ft (15 m) of a wire is measured for its distance to the wire; vegetation farther out is not measured, and whether any tree could strike the line if it fell is not assessed.
• Accuracy is the survey's. Omniris publishes no accuracy figure for its classification or clearance; the scanner, point density and georeferencing set what a distance can be relied on for.
• Temperatures come from stitched maps. Readings are taken from maps made from straight-down radiometric flights; close-up connector and splice photos are stored with their custody record, and the thermal layer on a 3D model is for display.

Sources

1. NERC, Reliability Standard FAC-003-5, Transmission Vegetation Management (applicability, R1–R7, measures, evidence retention, Table 2 MVCD, guidelines and technical basis). https://www.nerc.com/pa/Stand/Reliability%20Standards/FAC-003-5.pdf
2. ReliabilityFirst, "Enforcement Explained: Trends in vegetation management" (FAC-003-5 effective April 1, 2024; common root causes of violations). https://www.rfirst.org/resource-center/enforcement-explained-trends-in-vegetation-management/
3. ReliabilityFirst, 2025 RF Transmission Outage Assessment (vegetation-caused outages 2021–2024). https://www.rfirst.org/wp-content/uploads/2025/10/2025-RF-Transmission-Outage-Assessment.pdf
4. Tree Care Industry Association, ANSI A300 Part 7, Integrated Vegetation Management (IVM). https://treecareindustryassociation.org/business-support/ansi-a300-standards/part-7-integrated-vegetation-management-ivm/
5. Pacific Gas and Electric Company, Utility Standard TD-7103S, Vegetation Management Transmission Program, Rev. 4, effective January 27, 2025 (annual LiDAR patrol, ground patrol, second patrol, GO 95 Rule 35 / Appendix E, Appendix A clearance distances). https://www.pge.com/assets/pge/docs/outages-and-safety/outage-preparedness-and-support/td-7103s-vegetation-management-transmission-program.pdf
6. California Public Resources Code §4293 (power line clearance). https://california.public.law/codes/public_resources_code_section_4293
7. California Office of Energy Infrastructure Safety, "Energy Safety issues approvals of 2026–2028 wildfire mitigation base plans for Trans Bay Cable and Horizon West Transmission" (February 2026). https://energysafety.ca.gov/news/2026/02/09/energy-safety-issues-approvals-of-2026-2028-wildfire-mitigation-base-plans-for-trans-bay-cable-and-horizon-west-transmission/
8. T&D World, "How Drones Are Revolutionizing Power Line Inspections: Georgia Power's Success Story" (August 2024). https://www.tdworld.com/overhead-transmission/article/55131627/how-drones-are-revolutionizing-power-line-inspections-georgia-powers-success-story
9. Commercial UAV News, "How to grow your drone operations: a talk with Southern Company's UAS program manager Dean Barefield". https://www.commercialuavnews.com/energy/how-to-grow-your-drone-operations-a-talk-with-southern-company-s-uas-program-manager-dean-barefield
10. FirstEnergy, "FirstEnergy Using Helicopters and Infrared Technology for Vegetation Management Inspections" (press release, May 10, 2024). https://seekingalpha.com/pr/19721566-firstenergy-using-helicopters-and-infrared-technology-for-vegetation-management-inspections
11. M. Walker and G. A. Dahle, "Literature Review of Unmanned Aerial Systems and LIDAR with Application to Distribution Utility Vegetation Management", Arboriculture & Urban Forestry 49(3):144–156 (2023). https://auf.isa-arbor.com/content/49/3/144
12. IEEE 2821-2020, Guide for Unmanned Aerial Vehicle-Based Patrol Inspection System for Transmission Lines. https://standards.ieee.org/ieee/2821/7642/
13. EPRI, Project 35.001, Overhead Transmission Inspection and Assessment. https://transmission.epri.com/p35_overhead/pofs/p35001
14. Federal Aviation Administration, "Normalizing Unmanned Aircraft Systems Beyond Visual Line of Sight Operations" (proposed rule, Federal Register, August 7, 2025). https://www.govinfo.gov/content/pkg/FR-2025-08-07/html/2025-14992.htm
15. Commercial UAV News, "Part 108 proposed rule moves onto Office of Information and Regulatory Affairs" (July 2026). https://www.commercialuavnews.com/part-108-proposed-rule-moves-onto-office-of-information-and-regulatory-affairs
16. Tree Care Industry Association, ANSI A300 Standards ("Starting January 1, 2024, the standards are available as one consolidated document"). https://treecareindustryassociation.org/business-support/ansi-a300-standards/
17. International Society of Arboriculture store, ANSI A300 Tree Care Standards (2023), the ten A300 parts in one book; Clause 11: Integrated Vegetation Management (IVM). https://wwv.isa-arbor.com/store/product/4645
18. NERC, Report on Reducing the Risk of Wildfire Ignition by the Bulk Power System, filed with FERC in Docket No. RD25-9-000, May 1, 2026 (recommendation to revise FAC-003-5 for facilities between 100 kV and 200 kV). https://www.nerc.com/globalassets/who-we-are/legal--regulatory/filings--orders/nerc-filings-to-ferc/2026/wildfire-report-filing_signed.pdf

Sources were consulted in October 2026. Figures reported by a utility are labelled as such where they appear.

Glossary

As flown

Measured where things were at the moment of capture, without modelling how the conductor moves with load, heat and wind, or how vegetation grows.

BVLOS

Beyond visual line of sight: flying a drone farther than the pilot can see it. In the United States it needs a waiver today; the proposed Part 108 rule would create permits and certificates for it.

Canopy height model

A height map of whatever stands on the ground: the surface model minus the terrain model.

Clearance point

One patch of vegetation inside your clearance distances, with its closest distance to the wire, its height, its length along the line and its location.

Conductor

A wire of an overhead power line.

COPC

Cloud Optimized Point Cloud: a standard LAZ file arranged so a viewer can stream it.

Custody record

The sealed, independently timestamped history of everything that happened to a file or a finding.

DSM / DTM

Surface model (the top of everything: ground, vegetation, structures) and terrain model (bare ground).

FAC-003

NERC's Reliability Standard for transmission vegetation management; version 5 has been in effect since April 1, 2024.

Fall-in / grow-in

A tree falling onto a line, against vegetation growing up into it.

Finding

An Omniris work item with a place on the map, category, severity, status, assignee, evidence and history.

HFTD

High Fire-Threat District: California's designation for areas where utility lines carry elevated wildfire risk.

IVM

Integrated vegetation management: evaluating a right-of-way and choosing among control methods, including cultural, biological and chemical ones, to manage it (ANSI A300, Clause 11; formerly Part 7).

LAS / LAZ

The standard LiDAR file formats; LAZ is compressed LAS.

MVCD

Minimum Vegetation Clearance Distance: FAC-003's minimum distance between vegetation and a conductor, by voltage and altitude.

NAVD88

The North American Vertical Datum of 1988, the common reference for heights in the United States.

Right-of-way (ROW)

The strip of land along a line that the utility has rights to clear and maintain.

Wire zone / border zone

The IVM concept, recognised in ANSI A300's integrated vegetation management standard, of managing the area under the wires differently from the edges of the right-of-way.