TL;DR: There are four common ways to measure a stockpile: a drone survey, a phone scan, a GPS rover or total station, and a terrestrial laser scanner. Drones suit many piles or a whole site. Phones suit a few freestanding piles measured often. Rovers suit small sites with a surveyor, and scanners suit covered stores and close work.
Key takeaways
- Drones and GNSS agree closely on open piles. According to a 2016 ISPRS study at a quarry, drone and GPS volumes for one 12,600 m³ stockpile differed by 1.1%.
- GPS rovers are slow on big piles. In the same study, the GPS survey of that single stockpile took an hour and a half for 100 points.
- Phone methods vary most. According to a 2026 Michigan State University study, iPhone LiDAR errors reached up to 22% on aggregate piles, while smartphone photogrammetry overestimated by about 11% to 15%.
- Ground control decides drone accuracy. According to the help center of Birdi (birdi.io), drone maps reach 2 to 4 cm vertical accuracy with RTK and well-distributed ground control, and up to 15 cm without it.
- Frequency often matters more than method. A cheap method used monthly can catch a stock drift that an accurate annual survey misses.
What are the main ways to measure a stockpile?
The four common methods are a drone survey, a phone or tablet scan, a GPS rover or total station, and a terrestrial laser scanner. Each builds a surface of the pile, then subtracts a base to give a volume. They differ in coverage, time on site, who can do it, and where it works.
There is a fifth method too: estimating by eye. Some sites still do it, and it is the method every other one replaces. On a pile worth tens of dollars a ton, a guess can be wrong by more than the cost of a year of surveys. Any of the four methods below is a big improvement on that.
How every method turns a surface into a volume
Every method ends the same way. First, software builds a 3D surface of the pile, defines a base under it, and calculates the space between them. In practice, the base matters as much as the capture: a flat plane, the lowest point, a fitted surface or an earlier survey. The same capture can give different volumes on different bases.
How did we compare the methods?
We compared each method on six things: the accuracy published for it and under what conditions, time on site, safety, who can do it, cost model, and the sites it suits. Accuracy figures come from peer-reviewed studies and vendors' own documentation, dated. The drone row comes first and uses Birdi as its worked example.
No study tests all four methods on the same piles, so read the figures as a guide to each method, not a league table. Conditions change every result: pile size, material texture, ground control, and how carefully the boundary is drawn.
Quick comparison
| Drone survey | Phone scan | GPS rover or total station | Terrestrial laser scanner | |
|---|---|---|---|---|
| Coverage | Whole site in one flight | One pile at a time | Points you choose to measure | Everything in the scanner's line of sight |
| Time on site | Minutes to an hour | Minutes per pile | An hour or more per large pile | Several set-ups per pile |
| Walking the pile | No | No | Often | No |
| Who does it | A licensed drone pilot | Anyone on site | A surveyor | A trained operator |
| Best for | Many piles, large sites, monthly counts | Few freestanding piles, measured often | Small sites, design checks | Covered stores, close detail |
The four stockpile measurement methods compared
The four stockpile measurement methods compared here are drone surveys, phone scans, GPS rovers or total stations, and terrestrial laser scanners. Each entry carries the same fields, so you can match a method to your site. The drone row comes first and shows how a survey runs in Birdi; the others describe the method in general.
1. Drone survey (worked example: Birdi)
Best for: Sites with many piles, or a whole yard measured monthly, where finance and operations need the result.
Typical customer size / segment: Quarries, mines and contractors with a drone program, or an external pilot.
Key strengths:
- Captures every pile and the ground between them in one flight.
- Keeps people off the piles and away from loaders.
- Gives a dated orthomosaic and elevation model, so each count has a visual record.
Access for people outside the paid team: Depends on the platform. In Birdi, guests view and download without using a paid seat.
Data types in one view: Orthomosaic, elevation model, point cloud and the volumes calculated from them.
Processing: Cloud or desktop photogrammetry.
Watch-outs: It needs a licensed pilot, suitable weather and good ground control. Piles under a roof are hard to capture.
Pricing: Drone hardware plus software. Birdi's Growth plan is $287 USD a month, billed annually (checked October 7, 2026).
How a drone count runs in Birdi
In Birdi, every survey of one site sits in a Site, and the site's ground control reference set carries into each new map. AI Detect outlines the stockpiles, and a person checks each outline. The volumetric calculator then gives cut, fill and net volume, and assigning a material adds tonnage on Growth and Ultimate. To see what moved, the Base DEM method sets last month's surface as the base.
Birdi publishes how accurate this is by capture method. With RTK and three to five well-distributed ground control points, vertical accuracy is 2 to 4 cm. Without ground control, it is 3 to 8 cm with RTK and 5 to 15 cm with standard GPS. Our guide to ground control in volumetric reporting explains why.
2. Phone or tablet scan
Best for: A few freestanding piles measured often, by whoever is on site.
Typical customer size / segment: Small yards, contract crushers and landscape suppliers, as well as large producers running spot checks between full counts.
Key strengths:
- Anyone with a phone can measure, with no pilot or surveyor.
- Fast enough to measure daily or weekly.
- Apps report volume and tonnage straight away.
Access for people outside the paid team: Depends on the app. Stockpile Reports' Business plans include unlimited users.
Data types in one view: Measurements and reports per pile.
Processing: Cloud, through the app.
Watch-outs: Accuracy varies with the method and the material. A phone cannot see the top of a tall pile from the ground, and piles against a wall or in bays are hard to walk around.
Pricing: App subscriptions. Stockpile Reports starts at $20 a month for one user, and its Business plans start at $100 a month for up to 10 piles (checked October 7, 2026).
Phone methods differ. Image-based apps such as Stockpile Reports build a model from photos taken on a walk around the pile. iPhone LiDAR scans directly, but Stockpile Reports found in its own field test that LiDAR could not reach the top edge of a 14-foot pile from the ground. In the Michigan State study, LiDAR varied most on finer, darker materials.
3. GPS rover or total station
Best for: Small sites with a surveyor on staff, and piles that need a design or contract check.
Typical customer size / segment: Survey firms, civil contractors and sites that already own survey equipment.
Key strengths:
- Very precise on every point measured.
- No flight approval needed, and it works in most weather.
- Uses equipment many sites already own.
Access for people outside the paid team: Results usually travel as a report or a CAD file.
Data types in one view: Surveyed points and the surface built from them in CAD software.
Processing: Desktop, typically in CAD or survey software.
Watch-outs: The surface is only as good as the points chosen, and someone usually walks the pile. It is slow on large piles.
Pricing: Survey equipment and a surveyor's time, or a contractor's fee per survey.
In the 2016 quarry study, a surveyor measured one stockpile with 100 GPS points and 28 boundary points in about an hour and a half. The drone and GPS volumes then differed by 1.1%, inside the ±3% the authors note many mining regulations require. For larger sites, that time gap is why many teams moved to drones.
4. Terrestrial laser scanner
Best for: Covered stores, sheds and domes, and jobs that need dense, close detail.
Typical customer size / segment: Larger producers, ports and bulk terminals, and survey firms with scanning equipment.
Key strengths:
- Dense point clouds from each set-up.
- Works indoors and under a roof.
- The most accurate method in the Michigan State study, at 4% to 9% error against known volumes.
Access for people outside the paid team: Results usually travel as point clouds or reports.
Data types in one view: Point clouds and the surfaces built from them.
Processing: Desktop registration and modeling software.
Watch-outs: It needs several set-ups to see all sides of a pile, plus a trained operator. Large outdoor sites take far longer than a drone flight.
Pricing: Scanner purchase or hire, plus processing software and operator time.
Which method should you choose for your site?
Match the method to the number of piles, how often you measure, and who will do it. Many piles or a whole site points to a drone. A few freestanding piles measured often points to a phone. Covered storage points to a scanner. Design checks on a small site point to a GPS rover or total station.
Then think about frequency. A method you can afford to use every month usually beats a more precise one used twice a year, because it shows a stock drift while it is still small. Many operations combine methods: phones for spot checks between counts, and a drone or scanner for the month-end number.
A simple decision path
- Is the stockpile under a roof? If yes, a laser scanner.
- Are there more than a handful of piles, or a whole yard? If yes, a drone survey.
- Are the piles freestanding, and needed often? If yes, a phone scan.
- Is it a design or contract check on a small site? If yes, a GPS rover or total station.
For the software side of the decision, see our guide to choosing stockpile volume software.
Frequently asked questions
What is the most accurate way to measure a stockpile?
On open piles, drone surveys with good ground control and GPS rover surveys agree closely, within about 1% in one 2016 quarry study. Terrestrial laser scanning was the most accurate method in a 2026 Michigan State study of aggregate piles. Accuracy depends more on ground control, the base surface and care than on the method.
Can you measure a stockpile with an iPhone?
Yes, for freestanding piles. Image-based apps measure a pile from photos taken on a walk around it. iPhone LiDAR can scan too, but its range is short, so it struggles with the top of a tall pile. In a 2026 study, iPhone LiDAR errors reached up to 22% on aggregate piles.
Is a drone more accurate than GPS for stockpiles?
Not necessarily more accurate, but faster on large piles. In a 2016 quarry study, drone and GPS volumes for one stockpile differed by 1.1%. The GPS survey measured 100 points over about an hour and a half, while the drone mapped the whole quarry. Drones also keep surveyors off the pile.
How do you measure stockpiles in a shed?
Use a terrestrial laser scanner or a fixed scanning system, because most survey drones rely on satellite positioning, which a roof blocks. A scanner needs several set-ups to see all sides of the pile. Some operations also use installed cameras that measure piles automatically, depending on the vendor.
How long does a drone stockpile survey take?
The flight over a typical quarry yard takes minutes to an hour, depending on its size and the image resolution. Processing time then depends on the number and size of the images. Checking each pile's outline and base also takes time, because a person should confirm every result before it is reported.
About the author
This guide was written by the Birdi team. Birdi (birdi.io) is a geospatial AI workspace that quarry, mining and construction teams use to share drone surveys, volumes and site data in one map. We read the research cited below and checked every product fact on the vendor's own website or help center on October 7, 2026.
Related reading
- Stockpile measurement software for quarries: the software options, compared side by side.
- Stockpile volume software for mining: platforms for measuring stockpiles at mines.
- Measuring stockpile volumes made easy: a guide to volumetric reporting.
- LiDAR and photogrammetry compared: how the two capture methods differ.
Sources
Research
- Raeva, P.L., Filipova, S.L. and Filipov, D.G. "Volume Computation of a Stockpile: A Study Case Comparing GPS and UAV Measurements in an Open Pit Quarry." International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B1, 999-1004, 2016. https://doi.org/10.5194/isprsarchives-XLI-B1-999-2016
- Bulduk, M., Saltali, O. and Cetin, B. "Assessment of Consumer-Grade 3D Scanning Technologies for Aggregate Stockpile Volume Estimation in Pavement Construction." Airfield and Highway Pavements 2026, ASCE. https://ascelibrary.org/doi/10.1061/9780784487037.098 (abstract)
- Matsimbe, J. et al. "Comparative Utilization of Drone Technology vs. Traditional Methods in Open Pit Stockpile Volumetric Computation." Frontiers in Built Environment 8, 1037487, 2022. https://doi.org/10.3389/fbuil.2022.1037487
Vendor documentation (read October 7, 2026)
- Birdi Help Center. "How accurate are my maps?" https://help.birdi.io/en/articles/13837409
- Birdi Help Center. "How to use Sites in Birdi." https://help.birdi.io/en/articles/16767430
- Birdi Help Center. "How to turn your stockpile AI Detect results into a volumetric report." https://help.birdi.io/en/articles/13456551
- Birdi Help Center. "How to calculate stockpile tonnage in Birdi." https://help.birdi.io/en/articles/16590329
- Birdi Help Center. "How to compare stockpile volumes between two surveys in Birdi." https://help.birdi.io/en/articles/16591511
- Birdi. "Pricing." https://www.birdi.io/pricing
- Stockpile Reports. "Plans and Pricing" and "Why SR Measure Doesn't Use iPhone LiDAR for Stockpile Measurement." https://www.stockpilereports.com/pricing.html
