Glossary
A
- Accuracy Assessment
- The process of evaluating the spatial accuracy of drone-collected data by comparing survey outputs against known reference points (GCPs or checkpoints). Reported as RMSE (Root Mean Square Error) in horizontal and vertical components.
- As-Built Documentation
- Aerial surveys conducted after construction to verify that structures, grading, or installations match approved design plans. Commonly required for permitting, insurance, and owner acceptance. See: construction monitoring →
B
- BVLOS (Beyond Visual Line of Sight)
- Drone operations conducted beyond the pilot’s unaided visual range. BVLOS flights require FAA waivers and are used for long corridor surveys, pipeline inspections, and extended mapping missions.
C
- CAD-Ready Data (DWG/DXF)
- Drone survey outputs processed and formatted for direct use in AutoCAD or other CAD software. Includes 2D linework, contours, cross-sections, and 3D surface models derived from LiDAR or photogrammetric data.
- Clearance Analysis
- LiDAR-based measurement of the vertical and horizontal clearance between power lines and vegetation, ground, or structures. Used by electric utilities to verify NERC FAC-003 compliance and prevent outages.
- CloudPano
- A platform for hosting and sharing 360-degree virtual tours created from drone imagery. Skyflex delivers CloudPano-hosted tours for commercial real estate listings, facility documentation, and remote site walkthroughs.
- Confined Space Inspection
- The use of compact or specialized drones to inspect the interior of tanks, silos, boilers, and other confined spaces where human entry is hazardous or impractical. Reduces risk and enables detailed visual documentation. See: confined-space inspection →
- Corridor Mapping
- Aerial survey of a linear feature such as a transmission line, pipeline, road, or railroad right-of-way. Corridor mapping uses systematic flight paths to capture continuous, georeferenced data along the feature’s entire length. See: corridor mapping →
- Cut/Fill Analysis
- Volumetric calculation comparing existing ground elevation to a design surface, showing where material must be excavated (cut) or added (fill). Critical for earthwork planning and construction cost estimation. See: construction monitoring →
D
- DEM (Digital Elevation Model)
- A raster representation of the Earth’s bare-ground surface, with all vegetation and structures removed. DEMs are derived from LiDAR point clouds using ground-classification algorithms and are used for hydrological analysis, slope mapping, and floodplain modeling.
- Digital Twin
- A high-fidelity, georeferenced 3D representation of a real-world asset or environment created from drone data. Digital twins enable remote inspection, simulation, change detection, and virtual walkthroughs without physical site access. See: digital twin creation →
- DSM (Digital Surface Model)
- A raster elevation model representing the top surface of all features: ground, vegetation, and structures: as captured by the drone sensor. DSMs are useful for line-of-sight analysis, urban planning, and tree canopy assessment.
- DTM (Digital Terrain Model)
- Similar to a DEM, a DTM represents the bare-earth surface. In some applications, DTM may also include breaklines and terrain features for engineering-grade accuracy. Often used interchangeably with DEM but may carry additional structural data.
F
- FAA Part 107
- The Federal Aviation Administration regulation governing commercial drone operations in the United States. Part 107 certification requires passing a knowledge test and authorizes pilots to fly drones commercially within defined airspace restrictions. All Skyflex pilots are Part 107 certified.
- FLIR (Forward-Looking Infrared)
- A thermal imaging technology that detects infrared radiation emitted by objects, creating heat-map imagery. FLIR cameras mounted on drones are used to identify hotspots in electrical equipment, insulation failures, solar panel defects, and structural moisture intrusion. See: FLIR thermal imaging →
G
- GCP (Ground Control Point)
- A precisely surveyed reference marker placed on the ground and visible in drone imagery. GCPs are used during photogrammetric processing to georeference the dataset and achieve centimeter-level spatial accuracy. Typically established with RTK GPS equipment.
- GeoTIFF
- A standard raster image format that embeds geographic metadata (coordinate system, projection, extent) directly in the file. Orthomosaic maps and thermal rasters are commonly delivered as GeoTIFFs for direct import into GIS software like ArcGIS or QGIS.
- Georeferencing
- The process of assigning real-world geographic coordinates to drone imagery or point cloud data. Georeferencing can be accomplished through RTK GPS onboard the drone, GCPs, or post-processed kinematic (PPK) correction.
- GSD (Ground Sample Distance)
- The distance on the ground represented by a single pixel in a drone image. Lower GSD values indicate higher spatial resolution. A 1 cm/pixel GSD means each pixel covers a 1cm x 1cm area on the ground. GSD is controlled by flight altitude and camera specifications.
I
- Inspection Report
- A formatted document summarizing findings from a drone inspection mission. Includes annotated imagery, GPS-tagged defect locations, severity classifications, and recommendations. Delivered as PDF with embedded high-resolution photos.
L
- LiDAR (Light Detection and Ranging)
- An active remote sensing technology that uses laser pulses to measure precise distances to the ground and objects. Drone-mounted LiDAR sensors generate dense point clouds (millions of measurements per second) capable of penetrating vegetation canopy to reveal bare-ground terrain. Essential for transmission line surveys, topographic mapping, and volumetric analysis. See: aerial LiDAR scanning →
- LOS (Line of Sight)
- The requirement under FAA Part 107 that the drone remain within the visual line of sight of the remote pilot in command (RPIC) at all times. Operations beyond visual line of sight (BVLOS) require a specific FAA waiver.
N
- Nadir
- The point directly below the drone, or the downward-facing camera angle. Nadir imagery (camera pointing straight down) is used for orthomosaic mapping. Oblique imagery is captured at an angle from nadir to show vertical surfaces of structures.
- NDVI (Normalized Difference Vegetation Index)
- A calculated index using near-infrared and red spectral bands to measure plant health and vigor. NDVI maps from drone multispectral sensors are used in precision agriculture, environmental monitoring, and vegetation management for utilities.
- NERC FAC-003
- A North American Electric Reliability Corporation standard requiring transmission owners to inspect and manage vegetation within transmission line rights-of-way to prevent outages caused by tree contact. LiDAR-based drone surveys are widely used to demonstrate FAC-003 compliance. See: power line & utility inspection →
O
- Oblique Imagery
- Aerial photographs captured at an angle rather than straight down (nadir). Oblique imagery reveals vertical surfaces of buildings, towers, and structures that nadir imagery misses. Often used in combination with nadir photos for complete 3D reconstruction.
- Orthomosaic
- A geometrically corrected aerial image mosaic stitched from hundreds or thousands of individual drone photos. Orthomosaics are spatially accurate (like a map), allowing precise distance and area measurements directly on the image. Delivered as GeoTIFF.
P
- Photogrammetric Processing
- The computational process of extracting geometric and geographic measurements from overlapping drone photographs. Software like Agisoft Metashape or Pix4D uses feature matching, bundle adjustment, and dense image matching to produce point clouds, orthomosaics, and 3D models. See: aerial photogrammetry →
- Photogrammetry
- The science of making precise measurements from photographs. In drone surveying, photogrammetry uses overlapping images with known GPS positions to reconstruct accurate 3D terrain models, orthomosaic maps, and volume calculations without physical ground measurement. See: aerial photogrammetry →
- Point Cloud
- A dataset of millions of georeferenced 3D points representing the surfaces of objects and terrain captured by LiDAR or photogrammetric processing. Point clouds are delivered in .LAS or .LAZ format and can be viewed in software like CloudCompare, ArcGIS Pro, or AutoCAD.
- Point Density
- The number of LiDAR or photogrammetric points per unit area (commonly expressed as points per square meter). Higher point density provides more detail and accuracy. Transmission line surveys typically require 8-15 pts/m2 while topographic mapping may use 2-4 pts/m2.
R
- Radiometric Calibration
- The process of converting raw thermal or multispectral sensor data into physically meaningful values (temperature in degrees C or reflectance percentages). Radiometric calibration ensures that thermal images accurately represent actual surface temperatures for quantitative analysis.
- ROW (Right of Way)
- A strip of land over which a utility, pipeline, or transportation authority has legal rights for construction and maintenance. Drone corridor surveys of ROW are used to identify vegetation encroachment, assess condition, and plan maintenance activities.
- RTK GPS (Real-Time Kinematic GPS)
- A precision GPS technique that uses real-time correction data from a base station to achieve centimeter-level positioning accuracy. Drones equipped with RTK receivers can achieve survey-grade geolocation without traditional GCPs in many applications.
S
- Sag & Tension Analysis
- LiDAR-derived measurement of conductor sag (vertical deflection) and estimated conductor tension in transmission or distribution lines. Sag analysis helps utilities identify at-risk spans, plan reconductoring, and verify compliance with NERC standards.
- Sag Measurement
- Precise vertical measurement of conductor deflection between transmission towers using LiDAR point cloud data. Accurate sag measurement is essential for calculating line clearances and ensuring compliance with minimum clearance requirements. See: power line & utility inspection →
- SLAM (Simultaneous Localization and Mapping)
- A computational technique that allows a drone to build a map of an unknown environment while simultaneously tracking its own location within that map. SLAM-based drones enable GPS-denied indoor or confined space inspections. See: SLAM LiDAR ground-based scanning →
- Stockpile Volume
- Measurement of the volume of material in a pile (aggregate, soil, coal, lumber) using photogrammetric or LiDAR data compared against a base surface. Accurate stockpile volumes from drone surveys replace manual surveying and deliver results in hours rather than days. See: aerial photogrammetry →
- Survey Grade
- A level of spatial accuracy meeting professional surveying standards: typically plus or minus 2-5 cm horizontal and vertical accuracy. Drone surveys achieve survey grade through RTK GPS, GCPs, and rigorous accuracy validation against checkpoints.
T
- Thermal Anomaly
- A localized area of unexpected heat detected in thermal imagery. Thermal anomalies indicate potential defects such as failing electrical connections, insulation voids, water intrusion, or mechanical stress. Classified by severity for maintenance prioritization. See: FLIR thermal imaging →
- Thermal Imaging
- The capture and analysis of infrared radiation emitted by objects to create temperature-mapped images. Thermal drone surveys detect anomalies invisible to standard cameras, enabling non-destructive inspection of electrical, mechanical, and structural systems. See: FLIR thermal imaging →
V
- Vegetation Encroachment
- The growth of trees or vegetation into a transmission line ROW to within unsafe clearance distances of conductors. LiDAR surveys identify encroachment locations with precise GPS coordinates for targeted trimming and clearing operations. See: power line & utility inspection →
- 360 Virtual Tour
- An immersive, interactive panoramic experience created from drone or ground-level 360-degree imagery. Viewers can navigate through a space virtually, clicking between viewpoints. Skyflex delivers virtual tours via the CloudPano platform for commercial real estate, facility documentation, and remote client reviews. See: 360° virtual tours →