TL;DR: To choose stockpile volume software, check seven things: the accuracy the vendor publishes and under what conditions, how repeatable it is between surveys, how it uses your ground control, whether it measures change, whether it gives tonnage, how it reconciles with the weighbridge, and how many people touch the number before it is reported.
Key takeaways
- Stockpile numbers carry real money. According to the US Geological Survey, about 3,500 US quarries produced 1.5 billion tons of crushed stone in 2025, at an average of $18.50 a ton.
- Ground control matters more than the software brand. In a 2022 peer-reviewed quarry study, a drone survey with 5 ground control points came within 2.6% of the true stockpile volume.
- Repeatability is a different test from accuracy. Two surveys that are each accurate can still disagree. That difference lands in the month-on-month number.
- The base surface decides the volume. In 3 of 4 Pix4D community threads we read, users struggled to measure against a base surface and were told to finish the job in other software.
- Some reporting is monthly by law. Queensland requires a monthly return of quarry material taken from state land, even when none was taken.
What should stockpile volume software actually get right?
Stockpile volume software has to get three things right. The number must be accurate for this survey and repeatable against last month's. And it must reach the report without passing through several people and spreadsheets. A tool strong on accuracy but weak on the other two still causes arguments at month end.
The stakes are clear. According to the US Geological Survey, about 3,500 US quarries produced 1.5 billion tons of crushed stone in 2025, at an average of $18.50 a ton. At that price, a 2% error on a 50,000-ton stockpile is worth about $18,500. For many sites, the number is also an obligation. In Queensland, for example, operators taking quarry material from state land must "advise us of the amount of quarry material, if any, that you have taken" every month.
Most quarries already know their sales from the weighbridge. So the survey's job is different: it tells you what is left on the ground, and whether the gap between production, sales and stock makes sense. That makes consistency between surveys as important as accuracy in any one of them.
What are the seven questions to ask any vendor?
Seven questions separate stockpile software that produces a defensible number from software that produces a plausible one. They cover published accuracy, repeatability, ground control, measuring change, tonnage, reconciliation and the number of people who touch the result. Ask each vendor all seven, and ask to see the answer in its documentation.
1. What accuracy does the vendor publish, and under what conditions?
Ask for a published figure with its conditions, not a headline. Pix4D, for example, says relative accuracy is typically 1 to 2 times the ground sample distance horizontally. DroneDeploy labels RTK or PPK results without checkpoints "unvalidated accuracy." A figure without its conditions cannot be compared with anything.
Independent research backs the point. In a 2022 study in Frontiers in Built Environment, a drone survey of a quarry stockpile with 5 ground control points came within 2.6% of the measured volume. That was inside the study's ±3% allowable error. Its conditions were specific: a 1.44 cm ground sample distance and 70% image overlap.
2. How repeatable is it between surveys?
Ask how much two surveys of an unchanged pile can differ. Repeatability is what the month-on-month figure depends on, and it is usually worse than single-survey accuracy, because satellite geometry and atmospheric conditions change between flights. A vendor that publishes repeat-survey variance separately is telling you something useful.
3. Does it use your ground control, or its own hardware?
Some platforms are built around their own smart ground control targets. Others take ground control points you survey yourself. Either can work, but ask whether the same control can be reused on every survey of the site. According to a 2018 peer-reviewed study in Remote Sensing, accuracy improves as ground control points increase and are spread evenly. The ASPRS positional accuracy standard also asks for at least 30 independent checkpoints.
4. Can it measure change between two surveys, not just what is there now?
A single survey tells you what is on the ground. Month-end reporting often needs what moved: material added, removed and net. Ask whether the software can use an earlier survey's surface as the base for the latest one, with the same footprint, and whether the result is kept or overwritten when recalculated.
5. Does it turn volume into tonnage?
Finance, sales and royalties usually work in tons, not cubic yards or cubic meters. Ask whether the software applies a density per material, whether you can set your own density, and whether everyone on the team uses the same one. A density typed into a spreadsheet each month is where silent errors start.
6. How does it reconcile against the weighbridge?
Reconciliation compares opening stock, production, sales and closing stock. The survey supplies the closing figure, and the weighbridge supplies sales. Ask whether the software's output drops straight into that reconciliation, or whether someone retypes it. Differences between the two are normal, because density varies with moisture and how the pile was built.
7. Who touches the number between the flight and the report?
Count the handoffs. The pilot flies, someone processes, a surveyor draws the toes, someone else converts to tons, and finance pastes it into a report. Each step is a chance for a different base surface, density or rounding. The best answer is a short chain that anyone can audit afterward.
What goes wrong with stockpile software?
Public complaints about stockpile software are few, and they cluster in two places: the base surface under the pile, and the path from the software to the final number. Both themes point at the process around the measurement more than at the photogrammetry itself. The praise, when it comes, is about speed and ease of calculation.
We read four Pix4D community threads on stockpile volumes, from 2019 to 2022. In 3 of the 4, users struggled to measure against an earlier or custom base surface. Each was pointed to other software, such as Global Mapper, Civil 3D, QGIS or ArcGIS, to finish the job. One 2021 user put it plainly. Doing complicated volumes in other software is "a considerably more time consuming workflow." The fourth thread, from 2019, reported drone volumes 8 to 18% above a manual survey, on a flight with no ground control points.
DroneDeploy's own help center describes the same risk: the lowest-point base plane is very sensitive to where the volume's vertices sit and assumes flat ground. On Capterra, one 2021 DroneDeploy reviewer wanted to "present volume in tonnes to clients" in the report. Propeller's reviewers, by contrast, praise its stockpile tools: a 2024 survey manager called calculating stockpiles "a timesaver." Among 20 Propeller reviews, one 2025 reviewer said measurements sometimes take long and crash.
What does a monthly stockpile report look like in practice?
Here is a worked example of a monthly stockpile report in Birdi (birdi.io), a geospatial workspace for drone, 360 and design data. Each step answers one of the seven questions. The same routine works on most platforms that keep ground control and earlier surveys together for a site.
- Keep every survey in one Site. A Site groups every map of one location, and a ground control reference set uploaded once is available to every future survey of it.
- Find the piles. AI Detect outlines stockpiles on the new map. It does not calculate volumes by default: the user chooses the surface and base method, such as Linear Fit, and clicks Calculate.
- Set the material. Choose a material from the built-in density library, such as crushed rock at 1.60 t/m³. Or save a custom density to the workspace, so the whole team uses the same one. Tonnage is on Growth and Ultimate.
- Measure what moved. Import last month's elevation model, set it as the base (the Base DEM method), and read cut, fill and net in cubic meters and tons. Birdi's help center says using "the same GCPs across every survey is the single biggest improvement you can make to comparison accuracy."
- Export straight away. Recalculating overwrites the previous result, so export the table as CSV or a branded PDF for finance.
How accurate is the number in this example?
Birdi publishes its accuracy by capture method: 2 to 4 cm vertical with RTK and 3 to 5 well-distributed ground control points. Repeat surveys vary more: its table gives 2 to 5 cm between surveys with that setup, and 5 to 15 cm between RTK-only surveys with no ground control. For more on the reconciliation step, see our stockpile reconciliation guide.
Where does a person still decide?
At every step that matters. A person checks each pile outline, chooses the base method, picks the density and signs off the number. In Birdi, as in most platforms, AI detections are built to support expert review rather than replace it. For more on this, read about ground control for volume reports.
How should you choose stockpile volume software?
Shortlist two or three tools and test them on the same two surveys of your own site. Ask each vendor the seven questions, and count how many people touch the number in each workflow. The tool that gives a repeatable, auditable figure with the fewest handoffs is usually the right one.
Birdi is a sensible option if your quarry or mine wants the monthly number, the change since last month and the tonnage in one place. It also suits sites that share the result with finance and operations. A survey-led earthworks team that wants guided ground control hardware may prefer Propeller. And a surveyor who wants full control of each processing step will want a desktop tool such as Pix4D.
For a side-by-side of two of these options, see Birdi vs Propeller for mining.
To compare the wider field, see our list of stockpile volume software.
Frequently asked questions
How accurate are drone stockpile measurements?
With good ground control, drone stockpile measurements can come within a few percent of the true volume. In a 2022 peer-reviewed quarry study, a drone survey with 5 ground control points came within 2.6% of the measured volume. Without ground control, errors can be much larger, and repeat surveys usually vary more than a single one.
Do I need ground control points for stockpile volumes?
For a number you report or reconcile, yes. Ground control points tie the survey to real coordinates, and using the same points on every survey is what makes month-to-month comparisons reliable. RTK or PPK drones reduce the number needed, but checkpoints are still the way to prove accuracy rather than assume it.
How do you calculate stockpile tonnage from volume?
Multiply the volume by the material's bulk density: volume in cubic meters times density in tons per cubic meter gives tons. Crushed rock is often taken at about 1.6 tons per cubic meter, but density varies with moisture and compaction, so use a figure tested on your own material and keep it consistent.
How often should stockpiles be surveyed?
Most operations survey monthly, to match month-end stock reporting, and some survey weekly on high-value or fast-moving piles. The right frequency is set by your reporting and reconciliation cycle. Queensland, for example, requires a monthly return of quarry material taken from state land, even when none was taken.
Why do drone volumes differ from the weighbridge?
Because they measure different things. The weighbridge weighs what left the site, while the survey measures the volume of what remains. Converting volume to tons depends on density, which changes with moisture and how the pile was formed, and the base surface under each pile changes the volume too.
About the author
This guide was written by the Birdi team. Birdi (birdi.io) is a geospatial AI workspace that construction and mining teams use to share drone, 360 and design data in one map. We checked every product fact against each vendor's own site or help center on September 21 and 28, 2026, and read the forum threads and reviews ourselves. Each source is listed below.
Related reading
- Creating a stockpile volume report: step-by-step instructions for a volume report.
- How accurate drone data is: what drives precision in drone mapping.
- Propeller Aero alternatives: the options for teams leaving an earthworks platform.
- Birdi for mining and resources: how mine and quarry teams use one map for site data.
Sources
Government and research
- U.S. Geological Survey. "Stone (Crushed)." Mineral Commodity Summaries, February 2026. https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-stone-crushed.pdf
- Matsimbe, J., Mdolo, W., Kapachika, C., Musonda, I. and Dinka, M. "Comparative Utilization of Drone Technology vs. Traditional Methods in Open Pit Stockpile Volumetric Computation: A Case of Njuli Quarry, Malawi." Frontiers in Built Environment 8, 1037487, 2022. https://www.frontiersin.org/articles/10.3389/fbuil.2022.1037487/full
- Sanz-Ablanedo, E., Chandler, J.H., Rodríguez-Pérez, J.R. and Ordóñez, C. "Accuracy of Unmanned Aerial Vehicle (UAV) and SfM Photogrammetry Survey as a Function of the Number and Location of Ground Control Points Used." Remote Sensing 10(10), 1606, 2018. https://doi.org/10.3390/rs10101606
- Abdullah, Qassim A. "The ASPRS Positional Accuracy Standards, Edition 2." LIDAR Magazine, October 6, 2023. https://lidarmag.com/2023/10/06/the-asprs-positional-accuracy-standards-edition-2/
- Business Queensland. "Reporting and paying royalties for riverine quarry materials." Last updated October 24, 2022. https://www.business.qld.gov.au/industries/mining-energy-water/resources/quarries/riverine-materials/payment-royalties
User forums and reviews
- Pix4D Community. "15% Difference between Pix4d volumes and manual survey" (2019); "Volume base surface that conforms to actual DSM" (2020); "Calculate stockpile volumes against imported base surface" (2021); "Stockpile measurements" (2022). Read September 28, 2026. https://community.pix4d.com/t/15-difference-between-pix4d-volumes-and-manual-survey/8436 · https://community.pix4d.com/t/volume-base-surface-that-conforms-to-actual-dsm/11665 · https://community.pix4d.com/t/calculate-stockpile-volumes-against-imported-base-surface/17514 · https://community.pix4d.com/t/stockpile-measurments/21171
- Capterra. Propeller Aero reviews (20) and DroneDeploy reviews (9). Read September 21, 2026. https://www.capterra.com/p/179319/Propeller-Platform/reviews/ · https://www.capterra.com/p/197016/DroneDeploy/reviews/
Vendors
- DroneDeploy Help Center. "What baseplane should I use?" and "Choosing a High Accuracy Workflow." Checked September 21 and 28, 2026. https://help.dronedeploy.com/hc/en-us/articles/10330708951063 · https://help.dronedeploy.com/hc/en-us/articles/22885434354327
- Pix4D Support. "What is the relative and absolute accuracy of drone mapping?" Checked September 21, 2026. https://support.pix4d.com/hc/en-us/articles/202558889
- Birdi Help Center. "How to use Sites"; "How to upload GCP and prism reference sets to a site"; "How to turn your stockpile AI Detect results into a volumetric report"; "How to calculate stockpile tonnage"; "How to compare stockpile volumes between two surveys"; "How accurate is the volumetric calculator?" (all August 24, 2026, except Sites and reference sets); "How accurate are my maps?" (April 9, 2026). https://help.birdi.io/en/articles/16767430 · /16768238 · /13456551 · /16590329 · /16591511 · /10504763 · /13837409
Forum evidence comes from the Pix4D community. The DroneDeploy forum now redirects to its help center and could not be read, and Reddit, G2's full pages and TrustRadius were not read for this guide.
