Most confusion on a drone job is about words. The engineer asks for a DTM and gets a DSM. The realtor asks for aerials and gets a map. The strata council hears "BVLOS" and assumes something unsafe. This glossary gives everyone on the job the same meaning for the same word.
Above ground level. Drone altitude limits in Canada and the US are measured from the ground below, not from sea level.
Advanced certificate
Transport Canada's Pilot Certificate for Advanced Operations: an online exam plus an in-person flight review. Needed for controlled airspace, flying near people and near airports.
Basic certificate
Transport Canada's Pilot Certificate for Basic Operations: an online exam only. Uncontrolled airspace, more than 30 m from people not involved.
BVLOS
Beyond visual line of sight: the pilot cannot see the drone directly. Allowed in Canada under Level 1 Complex rules or an SFOC, and in the US by waiver until a new rule takes effect.
CARs Part IX
Part IX of the Canadian Aviation Regulations, the rules for remotely piloted aircraft systems.
Controlled airspace
Airspace where air traffic control provides service, usually around airports. Needs authorization from NAV CANADA in Canada, or the FAA in the US.
Drone Management Portal
Transport Canada's online system for registering drones, taking exams and managing certificates.
EVLOS
Extended visual line of sight: a trained visual observer watches the airspace while the drone flies beyond the pilot's own sight, within set limits.
FAA
Federal Aviation Administration, the US aviation regulator.
Flight review
An in-person practical assessment by a Transport Canada-recognized flight reviewer, required for the Advanced and Level 1 Complex certificates.
LAANC
Low Altitude Authorization and Notification Capability: the FAA system that gives near real-time authorization to fly in controlled airspace up to set ceilings.
Level 1 Complex
Canada's category for lower-risk BVLOS flights in uncontrolled airspace over unpopulated or sparsely populated areas, since November 4, 2025.
Medium drone
In Canada, a drone over 25 kg up to 150 kg. Advanced pilots may fly them within visual line of sight since November 2025.
Microdrone
A drone under 250 g. No registration or certificate in Canada, but safe-flying rules apply and advertised events need an SFOC.
NAV CANADA
The private, non-profit company that runs Canada's civil air navigation system and authorizes drone flights in controlled airspace.
NAV Drone
NAV CANADA's app for checking airspace and requesting authorization to fly in controlled airspace.
Occurrence report
A report to the regulator after an incident such as an injury, a collision or a fly-away. Which events are reportable is set by the rules.
Part 107
The FAA rule for small drones under 55 lb flown for any non-recreational purpose.
Part 108
The FAA's proposed rule for routine beyond visual line-of-sight operations, not yet in effect as of September 2026.
Part 137
The FAA rule for agricultural aircraft operations, which covers drones that dispense pesticides and other economic poisons.
Recency
Canada's requirement to have passed an exam, a flight review or approved recurrent training within the previous 24 months before flying.
Remote ID
The US requirement that drones broadcast identification and location, built in or through a module.
RPAS
Remotely piloted aircraft system: the drone, its control station and the link between them.
RPOC
RPAS Operator Certificate. A Transport Canada certificate for organizations, required for Level 1 Complex operations.
Safety assurance declaration
A manufacturer's declaration that a drone model meets Transport Canada's standard for a type of operation, such as flying near people or in controlled airspace.
SFOC
Special Flight Operations Certificate. Transport Canada permission for operations outside the standard categories.
Sheltered operation
A Canadian Advanced operation close to a building or structure (within 61 m horizontally and 30 m above it) where the drone may be out of the pilot's sight.
Site survey
The pilot's documented review of a site before flying: airspace, obstacles, people, take-off and landing areas and emergency plans.
TFR
Temporary flight restriction. A US notice that closes airspace for a fire, event or security reason.
Visual observer
A crew member who helps the pilot watch the drone and the airspace.
VLOS
Visual line of sight: the pilot or observer can see the drone with their own eyes, without binoculars.
Waiver
FAA permission to operate outside a specific Part 107 limit, with conditions.
Mapping and survey
Mapping, survey and accuracy terms
Term
Meaning
Checkpoint
A surveyed point on the ground not used in processing, used to test and report a map's accuracy.
Contours
Lines joining points of equal elevation, drawn at a set interval.
Cut and fill
The volume of material to remove (cut) or add (fill) to reach a design surface.
Datum
The reference that coordinates and heights are measured from, such as NAD83(CSRS) and CGVD2013 in Canada.
DSM
Digital surface model: heights of the top of everything, including buildings and trees.
DTM
Digital terrain model: bare-earth heights with buildings, vehicles and vegetation removed.
GCP
Ground control point: a marked, surveyed point used to tie a drone map to real coordinates.
GeoTIFF
An image file with coordinates built in, the usual format for orthomosaics and elevation models.
GNSS
Global navigation satellite systems, including GPS, GLONASS, Galileo and BeiDou.
GSD
Ground sample distance: the size of one image pixel on the ground.
LAS / LAZ
Standard file formats for point clouds; LAZ is compressed.
LiDAR
Light detection and ranging: a laser scanner that measures distance to build a 3D point cloud, and can often reach the ground under vegetation.
Mesh
A 3D surface made of connected triangles, usually textured with photos.
Nadir
Straight down. Nadir images are the base for orthomosaics.
Oblique
Angled images that capture the sides of buildings and structures.
Orthomosaic
A single stitched, straightened aerial image where distances and areas can be measured.
Overlap
How much each photo shares with the next, along the flight line (front) and between lines (side).
Photogrammetry
Measuring 3D shapes from overlapping photos.
Point cloud
A set of 3D points, often millions, that represents a surface or object.
PPK
Post-processed kinematic: correcting the drone's GNSS positions after the flight using base station data.
RMSE
Root mean square error: a common single number for the accuracy of checkpoints.
RTK
Real-time kinematic: correcting the drone's GNSS positions during flight from a base station or network.
Stockpile volume
The measured volume of a pile of material, calculated against a base surface.
Inspection
Inspection and thermal terms
Term
Meaning
Building envelope
The parts of a building that separate inside from outside: roof, walls, windows, doors.
Delta T
The temperature difference that makes thermal defects visible; thermal work needs enough of it.
Emissivity
How well a surface gives off heat. Shiny metal and glass have low emissivity and read falsely cool on a thermal camera.
Hot spot
An area on a solar panel that is hotter than it should be, often a failing cell, a diode or soiling.
Radiometric
Thermal imagery that records a temperature value for every pixel, not only a coloured picture.
Thermography
Using infrared cameras to see temperature differences.
Zoom inspection
Close visual inspection using an optical zoom camera from a safe distance.
Media
Real estate and media terms
Term
Meaning
3D virtual tour
A walk-through of a property built from scans or 360 images; Matterport is a format clients often ask for.
Bracketing
Taking several exposures of one scene and blending them so windows and shadows are both visible.
Floor plan
A measured drawing of a property's layout, often with room sizes.
Gimbal
The stabilized mount that keeps the camera steady and level.
Golden hour
The period after sunrise and before sunset when light is warm and low.
Twilight shoot
Photos taken just after sunset, when the sky still has colour and interior lights are on.
Vertical video
Video in a 9:16 frame for phones and social media.
Exterior cleaning
Cleaning and work-at-height terms
Term
Meaning
Exclusion zone
The area kept clear of people under or around a drone or work at height.
Rope access
Work at height by technicians on two independent ropes.
Runoff
Water and cleaning solution that comes off a building during washing.
Soft washing
Cleaning with low-pressure water and cleaning solution rather than high-pressure blasting.
Swing stage
A suspended platform lowered down a building for maintenance work.
Tethered drone
A drone connected to the ground by a cable or hose, for power, water or both.
As-built
A record of what was actually built, as opposed to what was designed.
Digital twin
A measured digital model of a site or building that is kept up to date.
Project record
In DroneLink, the single record for a site holding every order, flight, deliverable, review and invoice.
Version history
The record of each revision of a deliverable, so everyone can see what changed and when.
Next
Where to go from here
If a word on your quote or report is not here, ask the pilot or the surveyor to define it in writing and save that to the project record. To see the terms in practice, read preparing a site for a flight or browse inspection and mapping.
Questions
Questions
What does BVLOS mean?
Beyond visual line of sight: the pilot cannot see the drone directly. In Canada it is allowed under the Level 1 Complex rules or an SFOC; in the US it currently needs a waiver.
What is the difference between an orthomosaic and an aerial photo?
An aerial photo has perspective and distortion. An orthomosaic is stitched from many photos and straightened so distances and areas can be measured.
What does GSD mean in drone mapping?
Ground sample distance, the size of one pixel on the ground. A 2 cm GSD means each pixel covers 2 cm of ground.
What is an SFOC?
A Special Flight Operations Certificate from Transport Canada, needed for drone operations outside the standard Basic, Advanced and Level 1 Complex categories.
What is the difference between RTK and PPK?
Both correct the drone's GNSS position to centimetre level. RTK does it live during the flight; PPK does it afterwards from logged data.
What is a DTM?
A digital terrain model: the bare ground with buildings, vehicles and vegetation removed. Engineers use it for design and volumes.
What is LAANC?
The FAA's system for near real-time authorization to fly in controlled airspace near US airports, up to set altitude ceilings.
