Drone mapping: what drone mapping software makes and what rules apply
Drone mapping turns many overlapping photos into measured maps: the U.S. Geological Survey describes software that matches features across the photos to build 3D point clouds, surface models and orthomosaics.
- Drones in our GSD table
- 11
- Overlap between flight lines, USGS survey
- 70%
- Ground control against the accuracy wanted
- 3× better
- Part 107 height limit
- 400ft
How drone mapping works: overlapping photos and photogrammetry software
A drone flies set lines and takes photos that overlap; software then finds the same features in several photos and measures the ground from them.
Drone mapping uses overlapping photographs. On a survey the USGS flew at Post Point on Bellingham Bay, Washington, in June 2019, the drone followed pre-programmed autonomous flight lines spaced for about 70 percent overlap between photos from adjacent lines, and the camera fired once a second.
Drone mapping software then does the measuring with photogrammetry. The USGS calibration and validation team at EROS explains that such software uses a technique called Structure from Motion (SfM), which “combines photogrammetric principles (of 3D measurement from 2D images)” with dense matching of features between the images. Features found in several photos give a 3D point cloud, and a triangulated model built from that cloud is colored from the photos.
The USGS processed its own example in commercial photogrammetry software and notes that free and open software is available too. It counts the FAA's Part 107 rule, and open source or less expensive processing hardware and software, among the reasons drones became popular for mapping work.
In short
How much ground one pixel covers depends on the camera and the height; how accurate the map is depends on ground control, not on that pixel size. A flight that is not strictly for fun falls under Part 107, and selling a map as an authoritative survey can be land surveying under state law.
This page explains drone mapping from the documents of the U.S. Geological Survey (USGS), NOAA, the FAA, state law and the drone makers. It recommends no software and no drone. To see what one pixel covers for your drone, go to the GSD table.
What drone mapping software makes from drone data: orthomosaics, point clouds and 3D models
One flight gave the USGS both 2D and 3D maps: orthomosaic imagery, digital surface models and topographic point clouds.
From the Post Point photos the USGS made three products with SfM photogrammetry: digital surface models (DSM), orthomosaic imagery and topographic point clouds. One flight gave both 2D and 3D maps: orthomosaic imagery, and surface models and 3D point clouds.
- Point clouds
Point clouds: points in 3D, each from a feature the software found in several photos.
- 3D models
3D models: a triangulated model built from the point cloud and colored from the photos, a textured mesh.
How well those maps line up with the real ground rests on ground control (see accuracy). At Post Point the crew laid out nineteen temporary ground control points, tarps with cross patterns and chalk X marks, and measured them by post-processed kinematic (PPK) GPS from a base station about 3 mi (5 km) away.
Ground sample distance: how much ground one pixel covers
Ground sample distance (GSD) is the ground one pixel covers. Half the height, half the GSD.
DJI and the USGS state ground sample distance (GSD) in centimeters per pixel. DJI prints the Phantom 4 RTK's GSD as (H/36.5) cm per pixel, where H is the aircraft's height above the scene in meters. The USGS reports its Post Point flights the same way: flights at about 230 ft (70 m) above the ground gave a nominal GSD of 1.8 cm per pixel, and flights at about 115 ft (35 m) gave 0.9 cm. Half the height, half the GSD.
No document we could read prints the formula behind such figures, so this is the arithmetic we use, followed by the check that it holds:
- Equivalent sensor width = 43.2666 mm × photo width ÷ photo diagonal, both in pixels. We take 43.2666 mm (43.27 mm rounded) as the frame diagonal that a 35 mm-equivalent focal length refers to; the check below is why.
- GSD in cm per pixel = equivalent sensor width (mm) × height above the ground (m) × 100 ÷ (35 mm-equivalent focal length (mm) × photo width in pixels).
- Inches and width: inches = cm ÷ 2.54; the photo's width on the ground = GSD × photo width in pixels.
- Check: the same figure from the printed field of view, read as the diagonal. A drone is shown when the two agree within 10 percent, shown with a note within 50 percent, and left out beyond that.
The check: for the Phantom 4 RTK's 3:2 photo, 5472 pixels wide, with its 24 mm equivalent focal length, the arithmetic gives H/36.48 cm per pixel; DJI prints H/36.5. The USGS figures above halve with the height, as the arithmetic does.
Worked example: DJI Mini 4 Pro
- Inputs: 24 mm format-equivalent focal length, 82.1-degree field of view, largest photo 8,064 × 6,048 px (DJI Mini 4 Pro specs page).
- Equivalent sensor width: 43.2666 × 8064 ÷ 10080 = 34.61 mm.
- At 100 ft (30.48 m): 34.61 × 30.48 × 100 ÷ (24 × 8064) = 0.545 cm, or 0.21 in, per pixel.
- Higher up: twice the height, twice the figure: 0.43 in (1.09 cm) at 200 ft and 0.86 in (2.18 cm) at 400 ft.
- Photo width on the ground: 0.545 × 8064 = 4,396 cm, about 144 ft (44 m) at 100 ft.
- Check with the field of view: 0.53 cm per pixel, 3 percent below the focal-length figure.
Your drone's figure
The GSD table gives each drone's figure at 100, 200 and 400 ft, inches first.
See the GSD tableGSD at 100, 200 and 400 feet for each drone
The higher the drone, the more ground one pixel covers: each figure doubles from 100 to 200 ft and again to 400 ft.
The table gives the GSD of 11 drones from our spec data at 100, 200 and 400 ft above the ground, inches first. The figures are for the largest photo each maker prints; the sensor comes from our spec data. To set two drones side by side on every spec, use our drone comparison tool.
| Drone and camera figures used | At 100 ft | At 200 ft | At 400 ft | Photo width at 100 ft |
|---|---|---|---|---|
| DJI Air 3S1-inch CMOS; 24 mm equivalent; 8,192 × 6,144 px; U.S. page | 0.21 in (0.54 cm) | 0.42 in (1.07 cm) | 0.85 in (2.15 cm) | 144 ft (44 m) |
| DJI Flip1/1.3-inch image sensor; 24 mm equivalent; 8,064 × 6,048 px; U.S. page | 0.21 in (0.55 cm) | 0.43 in (1.09 cm) | 0.86 in (2.18 cm) | 144 ft (44 m) |
| DJI Mavic 4 Pro4/3 CMOS; 28 mm equivalent; 12,288 × 8,192 px; UK page (no U.S. page) | 0.13 in (0.32 cm) | 0.25 in (0.64 cm) | 0.50 in (1.28 cm) | 129 ft (39 m) |
| DJI Mini 31/1.3-inch CMOS; 24 mm equivalent; 8,064 × 6,048 px; U.S. page | 0.21 in (0.55 cm) | 0.43 in (1.09 cm) | 0.86 in (2.18 cm) | 144 ft (44 m) |
| DJI Mini 3 Pro1/1.3-inch CMOS; 24 mm equivalent; 8,064 × 6,048 px; U.S. page | 0.21 in (0.55 cm) | 0.43 in (1.09 cm) | 0.86 in (2.18 cm) | 144 ft (44 m) |
| DJI Mini 4 Pro1/1.3-inch CMOS; 24 mm equivalent; 8,064 × 6,048 px; U.S. page | 0.21 in (0.55 cm) | 0.43 in (1.09 cm) | 0.86 in (2.18 cm) | 144 ft (44 m) |
| DJI Mini 4K1/2.3-inch CMOS; 24 mm equivalent; 4,000 × 3,000 px; user manual | 0.43 in (1.10 cm) | 0.87 in (2.20 cm) | 1.73 in (4.40 cm) | 144 ft (44 m) |
| DJI Mini 5 Pro1-inch CMOS; 24 mm equivalent; 8,192 × 6,144 px; UK page (no U.S. page) | 0.21 in (0.54 cm) | 0.42 in (1.07 cm) | 0.85 in (2.15 cm) | 144 ft (44 m) |
| DJI Neo1/2-inch image sensor; 14 mm equivalent; 4,000 × 3,000 px; U.S. page | 0.74 in (1.88 cm) | 1.48 in (3.77 cm) | 2.97 in (7.54 cm) | 247 ft (75 m) |
| DJI Neo 21/2-inch CMOS; 16.5 mm equivalent; 4,000 × 3,000 px; UK page (no U.S. page) | 0.63 in (1.60 cm) | 1.26 in (3.20 cm) | 2.52 in (6.39 cm) | 210 ft (64 m) |
| Potensic ATOM 21/2-inch CMOS; 26 mm equivalent; 8,000 × 6,000 px; maker's page | 0.20 in (0.51 cm) | 0.40 in (1.01 cm) | 0.80 in (2.03 cm) | 133 ft (41 m) |
Ground sample distance (GSD) for 11 drones at 100, 200 and 400 ft above the ground: how much ground one pixel of the largest photo covers, computed from the format-equivalent focal length and the photo size each maker prints. Sensor from our spec data.
Notes on the figures
- Read on DJI's UK pages: DJI Mavic 4 Pro, DJI Mini 5 Pro and DJI Neo 2 have no DJI U.S. product page.
- DJI Mavic 4 Pro: DJI's page does not say whether its 72-degree field of view and 28 mm equivalent describe the 3:2 photo or the 4:3 sensor, so this row may be off by about 6 percent.
- DJI Mini 4K: figures from DJI's user manual, as DJI has no specs page for it.
- DJI Neo 2: a wide lens. Its printed field of view gives a figure 32 percent above the one from its focal length; the table prints the focal-length figure.
- Largest photo: each row uses the largest photo size its maker prints. A smaller photo mode spreads the same view over fewer pixels, so each pixel covers more ground.
Left out of the table
- DJI Avata 2: its printed field of view gives a figure 150 percent above the one from its focal length, too far apart to print either.
- Antigravity A1: its camera is a 360-degree camera, and its 55 MP photo (10496 × 5248) is a panorama, not a downward photo.
- HOVERAir X1 PRO: the maker's page gives a 1/2-inch sensor and a 104-degree field of view but no photo size in pixels and no focal length.
Accuracy comes from ground control points and RTK, not from GSD
A small GSD does not make a map accurate. Ground control points, at least three times as accurate as the map you want, set its accuracy.
A small GSD does not make a map accurate. The USGS guidelines for calibrating drone imagery (Open-File Report 2023-1033, published July 25, 2023) say ground control points and the quality of tie points set a drone map's geometric accuracy “regardless of the ground sample distance”.
- Three times
Control three times better: the ground control points must be at least three times as accurate as the accuracy wanted from the drone imagery.
- An example
An example: a dataset with a 0.4 in (1 cm) GSD may be good to only about 2.4 in (6 cm, 1 sigma) when its control points are good to 0.8 in (2 cm). The USGS warns against assigning higher accuracy because the GSD is smaller.
- RTK
RTK control points: control points measured with real-time kinematic (RTK) solutions are usually good to about 0.8 to 1.2 in (2 to 3 cm, 1 sigma), so the imagery can be checked only to about 2.4 in (6 cm); total station methods serve higher accuracy.
- Measuring
How control is measured: with survey-grade GNSS receivers, or GNSS plus a total station. The best, subcentimeter results use total stations with published benchmarks kept by the National Geodetic Survey or a state department of transportation.
- Tie points
Tie points: each should be seen from at least six camera positions, so that it appears from opposing flight lines.
- Checking
Checking accuracy: the report cites the ASPRS positional accuracy standards of 2014 as calling for at least 30 points to assess a dataset's positional accuracy.
- Height
Horizontal and vertical: drone imagery usually has high horizontal (x-y) accuracy because the aircraft flies low; the vertical accuracy of the point cloud often depends on the texture of the surface.
Free federal control: NOAA OPUS and the CORS Network
NOAA's National Geodetic Survey (NGS) offers two free services. Its Online Positioning User Service (OPUS) gives “free access to high-accuracy National Spatial Reference System (NSRS) coordinates” from an uploaded GPS data file: static data of at least 15 minutes and at most 48 hours, with the antenna unmoved. NGS says data for setting or updating control in the current NSRS must reach it by January 13, 2027, ahead of the new datums.
The NOAA CORS Network's data are distributed free of charge, and NGS says post-processed coordinates “can approach a few centimeters” horizontally and vertically.
What DJI states for the Phantom 4 RTK
DJI gives the Phantom 4 RTK's RTK positioning accuracy as 1 cm + 1 ppm horizontal and 1.5 cm + 1 ppm vertical (RMS); 1 ppm adds 1 mm of error for each kilometer from the base. DJI says real mapping accuracy depends on light, ground patterns, height and software, and its FAQ says orthoimages made from Phantom 4 RTK photos with select software and no ground control points showed an absolute accuracy of roughly 2 in (5 cm). These are DJI's own figures, not a USGS finding.
What one state department of transportation asks of a survey camera
The North Carolina Department of Transportation's sheet “UAS Camera Requirements for Survey Quality Mapping” (last updated August 13, 2020) shows what one survey client asks. It is not a verdict on any drone in our table: none was checked against it.
- Global (mechanical) shutter only, rolling shutters not acceptable; a fixed focal length, non-fisheye lens; 20 to 102 MP.
- An output pixel size (GSD) of 0.11 ft or less at 400 ft above the ground.
- Georeferencing by an onboard or added survey-grade GNSS system.
- Forward overlap of at least 85 percent and side overlap of at least 80 percent; rotary-wing aircraft preferred.
- Wind of 15 mph or less, no precipitation, 32°F or warmer, and flights between 10 am and 2 pm to keep shadows short.
- Ground survey control spread across the project before any flight.
Limits of drone mapping flights: Part 107 and recreational rules
A mapping flight that is not strictly for recreation falls under Part 107; the recreational rules of 49 U.S.C. 44809 cover only a flight that is.
Each row below is one limit, with the rule of each rulebook that sets it and the guide on this site that covers it.
The limits on a mapping flight, one row per limit: Part 107 (14 CFR part 107) for any flight that is not strictly for fun, and the recreational rules (49 U.S.C. 44809) in lines of their own.
- Purpose of the flight
Flying for fun (49 U.S.C. 44809): The flight is strictly for recreational purposes; a flight that is not falls under Part 107.49 U.S.C. 44809(a)(1)
Our guide: Drone license guide
- Who flies
Part 107: Whoever works the controls holds a remote pilot certificate with a small UAS rating, or is directly supervised by a remote pilot in command who can take control at once.14 CFR 107.12(a)
Flying for fun (49 U.S.C. 44809): Pass the aeronautical knowledge and safety test and keep proof of passing.49 U.S.C. 44809(a)(7)
Our guide: Drone license guide, TRUST certificate
- Height
Part 107: No higher than 400 feet above ground level, unless the drone stays within a 400-foot radius of a structure and no higher than 400 feet above its top.14 CFR 107.51(b)
Flying for fun (49 U.S.C. 44809): In Class G airspace, from the surface to not more than 400 feet above ground level, and all airspace and flight restrictions apply.49 U.S.C. 44809(a)(6)
Our guide: How high can a drone fly
- Line of sight
Part 107: The remote pilot, any visual observer and the person at the controls must be able to see the drone for the whole flight, with no aid but corrective lenses.14 CFR 107.31(a)
Flying for fun (49 U.S.C. 44809): Flown within the visual line of sight of the operator or of a visual observer co-located and in direct communication with the operator.49 U.S.C. 44809(a)(3)
Our guide: Line of sight and range
- Airspace near airports
Part 107: Prior authorization from Air Traffic Control in Class B, C or D airspace or the surface area of Class E airspace designated for an airport.14 CFR 107.41
Flying for fun (49 U.S.C. 44809): Prior authorization from the FAA Administrator or designee in Class B, C or D airspace or the surface area of Class E airspace designated for an airport.49 U.S.C. 44809(a)(5)
Our guide: LAANC authorization
- Over people
Part 107: No flight over a person unless that person takes part in the operation, is under a covered structure or inside a stationary vehicle, or the flight meets one of the operational categories of subpart D.14 CFR 107.39
Our guide: Drone license guide
- Over moving vehicles
Part 107: Flight over people inside moving vehicles only under the conditions of the operational categories.14 CFR 107.145
Our guide: Drone license guide
- Registration
Part 107: The operator complies with 14 CFR 91.203(a)(2).14 CFR 107.13
Flying for fun (49 U.S.C. 44809): The aircraft is registered and marked under chapter 441 of title 49.49 U.S.C. 44809(a)(8)
Our guide: Registration helper
- Weight
Part 107: A small unmanned aircraft weighs less than 55 pounds on takeoff, including everything on board or attached.14 CFR 107.3
Our guide: Drone license guide
- Waivers
Part 107: A certificate of waiver may allow a deviation from listed sections, among them 107.31 (line of sight), 107.39 (over people), 107.41 (airspace) and 107.51 (altitude, speed, visibility).14 CFR 107.205
Our guide: How high can a drone fly
Which class of airspace a mapping site lies in, and how to read it on sectional charts, is in our guide to drone airspace classes. Near an airport, our LAANC guide shows how authorization is asked for.
When drone mapping becomes land surveying: state licensing
When a map deals in authoritative locations, the national model law calls it surveying, and California, Florida and North Carolina write photogrammetry into their surveying laws.
NCEES, the national body of state licensing boards, publishes a Model Law and Model Rules as a guide for its member boards, to be fitted to each state; they are not a law. In the model, mapping is the practice of surveying when it deals in authoritative locations, meaning presented as trustworthy and meeting the positional accuracy for a feature, object or boundary; maps for planning or general information are left out. California, Florida and North Carolina write photogrammetry into their own surveying laws.
When mapping is surveying: the national model law for state licensing boards, and the law of the three states this page covers, each in its own words as read, with the document and the section under it.
- National model
What surveying is: Surveying means professional services using sciences such as mathematics, geodesy and photogrammetry to make geometric measurements of the earth and turn them into survey products such as maps and data.NCEES Model Law (a model for state boards, not a law), Model Law 110.20 B.3
“Authoritative”: Authoritative means presented as trustworthy and competent, with a description that meets or exceeds the positional accuracy for a feature, object or boundary.NCEES Model Law (a model), Model Law 110.20 N
Work for a licensed surveyor: Under a professional surveyor: maps or georeferenced databases of authoritative locations; original data acquisition for authoritative location in themes that include orthoimagery and elevation; certification of positional accuracy.NCEES Model Rules (a model), Model Rules 210.25 A.1-A.3
What is not surveying: Measurements used as a reference for planning, infrastructure management and general information, and general maps such as guides or illustrations, are not the practice of surveying.NCEES Model Rules (a model), Model Rules 210.25 B
- California
The statute: Land surveying includes determining the configuration or contour of the earth's surface or the position of fixed objects by applying the principles of mathematics or photogrammetry.California Business and Professions Code, Cal. Bus. and Prof. Code 8726(a)(2)
The board on drone work: Drone flight planning, piloting and obtaining photography are not regulated by the Professional Land Surveyors' Act; creating a topographic survey or overlaying a boundary on an orthorectified photo for a client is land surveying.California board bulletin (the board's reading, 2017), BPELSG Bulletin, Spring 2017
- Florida
The statute: A surveyor and mapper determines facts of size, shape, topography and location through direct measurement or accepted photogrammetric procedures; the practice includes photogrammetric control.Florida Statutes chapter 472, Fla. Stat. 472.005(3), (4)(b)
Photogrammetrist: A photogrammetrist is a person in the practice of surveying and mapping using aerial or terrestrial photography or other images.Florida Statutes chapter 472, Fla. Stat. 472.005(8)
Who the law does not cover: The list of persons the chapter does not apply to names federal employees, engineers, contractors doing layout, appraisal mappers and supervised subordinates; it names no drone or aerial photography operator.Florida Statutes chapter 472, Fla. Stat. 472.003
- North Carolina
The statute: Land surveying covers information gathered by ground measurement, aerial photography or satellite positioning, and includes finding the contour of the earth's surface by mathematics or photogrammetry and creating GIS data for land surveying.North Carolina General Statutes chapter 89C, N.C.G.S. 89C-3(7)
Three states only
This page covers those three states only. In every other state, that state's own law and licensing board decide, and this page does not say what they decide. The California board's reading is a newsletter article of 2017, not a statute. For drone laws by state, which are not about surveying licenses, see our state drone laws.
Drone mapping in precision agriculture and other work
On farms drones are used mostly for crop mapping, livestock monitoring, land surveying and spraying; federal science maps with them too.
The USDA's Economic Research Service, in its report on precision agriculture, says drones, aircraft and satellite imagery are used on farms mostly for crop mapping, livestock monitoring, land surveying, crop spraying and crop dusting. Our guide to drones in agriculture covers those farm applications and their rules.
Federal science maps with drones too. The USGS timed its Post Point survey to a spring low tide to map as much exposed ground as possible, with a camera that had a global shutter. Its National Uncrewed Systems Office, set up on May 8, 2008 inside the National Land Imaging Program, recommends best practices for drone data collection and supports Department of the Interior remote pilots.
For what the official wage figures say about drone work, see our drone pilot salary guide.
Related pages
More drone work, and the rules for where you can fly.
Questions about drone mapping
What is the purpose of drone mapping?
To measure the ground in 3D from overlapping 2D photos. The USGS describes software that combines the principles of 3D measurement from 2D images with matching of features between photos, and its own drone survey delivered digital surface models, orthomosaic imagery and topographic point clouds.
Why did the U.S. ban DJI drones?
DJI drones, with all other foreign-produced drones, have been on the FCC Covered List since December 22, 2025. New DJI models cannot get FCC equipment authorization, so they cannot be legally marketed or imported; models authorized before the listing may still be imported and sold. Our DJI ban guide covers the background and what it means for owners.
Is there free drone mapping software?
Yes. The USGS notes that “free and open software are available for use” for this processing. One example is OpenDroneMap: its project page describes its ODM as an open source command line toolkit to process aerial images, created in 2014. This page does not rank software.
Do I need a license to sell drone maps?
For the flight, yes: under Part 107, whoever works the controls holds a remote pilot certificate or is directly supervised by a remote pilot in command who can take over at once. For the map, it depends on the state. The national model law puts maps of authoritative locations, and certifying their positional accuracy, under a professional surveyor, and California, Florida and North Carolina write photogrammetry into their surveying laws; each state's own law and board decide.
How accurate is a drone map?
About as accurate as its ground control. The USGS says control points measured with RTK are usually good to about 0.8 to 1.2 in (2 to 3 cm), so the imagery can be checked only to about 2.4 in (6 cm). For its Phantom 4 RTK with select software and no ground control points, DJI's FAQ states roughly 2 in (5 cm): DJI's own figure.
Sources Documents are named, not linked. The research data was read on November 14, 2026, and the page was last checked on November 14, 2026.
USGS and NOAA
- USGS EROS Calibration and Validation, Uncrewed Aerial Systems
- USGS Open-File Report 2023-1033, Guidelines for calibration of uncrewed aircraft systems imagery, July 25, 2023
- USGS data release, aerial imagery and structure-from-motion data products, UAS survey of the intertidal zone at Post Point, Bellingham Bay, Washington, June 2019
- USGS National Uncrewed Systems Office
- NOAA National Geodetic Survey, OPUS: Online Positioning User Service
- NOAA National Geodetic Survey, NOAA CORS Network
Flight rules
- 14 CFR 107.3, 107.12, 107.13, 107.31, 107.39, 107.41, 107.51, 107.145 and 107.205 (eCFR, current to November 12, 2026)
- 49 U.S.C. 44809, Office of the Law Revision Counsel, release point Public Law 119-142
Surveying law
- NCEES Model Law and NCEES Model Rules, August 2025
- California Professional Land Surveyors' Act, 2026 edition: Business and Professions Code 8726
- California Board for Professional Engineers, Land Surveyors, and Geologists, Bulletin, Spring 2017
- 2026 Florida Statutes 472.003 and 472.005
- North Carolina General Statutes 89C-3
Makers and others
- DJI Air 3S specs page, U.S. page
- DJI Avata 2 specs page, U.S. page
- DJI Flip specs page, U.S. page
- DJI Mavic 4 Pro specs page, UK page (DJI has no U.S. page for it)
- DJI Mini 3 specs page, U.S. page
- DJI Mini 3 Pro support page, U.S. page
- DJI Mini 4 Pro specs page, U.S. page
- DJI Mini 4K user manual
- DJI Mini 5 Pro specs page, UK page (DJI has no U.S. page for it)
- DJI Neo specs page, U.S. page
- DJI Neo 2 specs page, UK page (DJI has no U.S. page for it)
- Potensic ATOM 2 specs page
- DJI Phantom 4 RTK specs and FAQ, U.S. page
- North Carolina Department of Transportation, UAS Camera Requirements for Survey Quality Mapping, last updated August 13, 2020
- USDA Economic Research Service, Precision Agriculture in the Digital Era: Recent Adoption on U.S. Farms (EIB-248), February 2023
- FCC Public Notice DA 25-1086 and FCC Covered List
- OpenDroneMap, the project's home page
Photos: DJI press images. USGS (public domain).