How Omniris turns a drone flight over a coal yard, an aggregates plant, a port terminal or a salt barn into period-end stockpile volumes and tonnages, with the method, the density and the uncertainty written next to every number, and a tamper-evident record that a controller, an auditor or a lender can check for themselves.
Coal at a power station, aggregate at a quarry or ready-mix plant, wood chips on a port terminal, salt for the winter roads, fertilizer, scrap: bulk material sits on the balance sheet as a number that nobody can count by hand. At every period end someone has to turn a pile into tons, the controller has to book the difference between the books and the pile, the external auditor has to be satisfied that the quantity exists, and, where the inventory secures a loan, the lender's field examiner wants to see it too.
Traditionally that number comes from a surveyor walking the pile with a GPS pole, or from a manned aerial survey a couple of times a year, multiplied by a density, either a handbook figure or one tested on the material. Drones made the measurement faster and denser and took people off the piles. What they did not automatically provide is a record that the person who has to rely on the number can check: which flight, which surface, which base, which density, who changed the boundary, and whether anything was altered after the fact.
Omniris does both halves:
Draw the pile's boundary on the map and get its volume from the full-resolution surface model, with a plus-or-minus on every number, a choice of six base surfaces and a warning when the boundary is drawn badly.
Give a density, its state (bank, loose or compacted) and any swell or shrink factor, and get tonnage, labelled as a nominal book density or a site-tested one.
A saved measurement on a site is measured again on every new flight that covers it, so the month-end series fills itself. The site's inventory card totals the latest tonnage across its piles.
The imagery and the maps carry a signed, independently timestamped chain of custody, and every change to a measurement and every evaluation is sealed into the same ledger. Legal holds and retention keep the period-end evidence intact.
A read-only share, a frozen snapshot, or a link to the site's map, with an optional password, on which the auditor or the lender's examiner can open the reports, export the numbers and run their own check measurements.
Plan the flight, check the airspace, and hire a pilot through the Omniris marketplace on a weekly, monthly or quarterly cycle, or fly with your own team.
Omniris produces the measurement and a verifiable record of how it was made. Your accountants book it, your auditors judge it and, where a contract or regulator requires one, a licensed surveyor certifies it, each with the full record in front of them.
A stockpile count is a measurement problem wrapped in an accounting problem. The tonnage in the ledger moves with every truck, railcar, conveyor and ship; the pile on the ground is what is actually there. At regular intervals the two are reconciled, and the difference is booked. This section describes who needs that count, how it has been taken, how density turns it into tons, and where drones have come in.
| Who | Why they need a physical count | What governs it |
|---|---|---|
| Controller / CFO | Book-to-physical reconciliation at month, quarter or year end; writing up or down the difference. | The company's own close process and inventory policy. |
| External auditor (public companies) | Satisfy themselves that the inventory quantity exists. Where inventory quantities are determined solely by a physical count at or near the balance-sheet date, the auditor is ordinarily present at the count and satisfies themselves, by observation, tests and inquiries, that the counting methods are effective; if the auditor has not become satisfied that way, tests of the records alone are not enough and some physical counts must be made or observed [1]. | PCAOB AS 2510, Auditing Inventories [1]; AS 1105, Audit Evidence, and AS 1210, Using the Work of an Auditor-Engaged Specialist, when a specialist's work is relied on [2][3]. |
| External auditor, material held by others | Material stored at a terminal or warehouse operated by someone else. The auditor ordinarily obtains direct written confirmation from the custodian and, where the inventory is a significant proportion of current or total assets, applies further procedures, which can include observing physical counts of the goods [1]. | PCAOB AS 2510, paragraph .14, Inventories Held in Public Warehouses [1]. |
| Electric utility (coal) | Coal is carried as fuel stock on the balance sheet and cleared to fuel expense as it is burned; the utility must keep records of the quantity, heat content and cost of each fuel used [9]. Survey adjustments then true the books to the pile. | FERC Uniform System of Accounts, 18 CFR Part 101, accounts 151 (Fuel stock) and 501 (Fuel) [9]; state commissions, for example the Florida PSC, which, under a 1997 commission order, receives notice of the coal inventory survey adjustments a utility booked in a given month, comparing coal tons per physical inventory with coal tons per books [10]. |
| Lender (asset-based loans) | Inventory in the borrowing base. Field audits physically inspect collateral and test its value; they are done before a loan is booked and regularly after, "often quarterly but more frequently if risk dictates" [12]. The borrower is normally required to certify the amount, type and condition of inventory and to let the lender or an independent firm audit it [12]. | OCC Comptroller's Handbook, Asset-Based Lending [12]. |
Volume methods have moved from tape measures to dense 3D surfaces. The methods below are all still in use somewhere.
| Method | How it works | Known weaknesses |
|---|---|---|
| Walking wheel and bills of lading | Walk the pile with a measuring wheel and estimate a shape, or count what was delivered on paper. In a survey of 33 state transportation (DOT) staff, walking-wheel estimation (15 %) and bills of lading (13 %) were among the most widely used methods [15]. | Simple estimating techniques: less accurate, slower and in the end more expensive than digital measurement, with the data largely kept on paper [15]. |
| GPS base and rover (walking survey) | A surveyor walks around and over the pile recording points with a GNSS pole; survey software builds the surface. GNSS RTK rovers and handheld devices were 11 % of the DOT responses [15]. | Resource-intensive and puts staff on the slopes — one state DOT did these surveys on snow- and ice-covered piles in winter [15]. Against a lidar benchmark, GPS topographic surveys repeated within 6 %, against 2 % for digital measurement [15]. In one utility audit the traditional method meant traversing the coal pile with a 6.6 ft (2 m) GPS pole, more than 1,200 points over about four hours [14]. |
| Laser scanner / total station | Shoot the pile with a total station, or scan it with a terrestrial laser scanner (laser was 10 % of the DOT responses) [15]. | Survey-grade and resource-intensive; laser scanning is the benchmark the other methods are checked against [15]. |
| Manned aerial photogrammetry | A fixed-wing aircraft photographs the site [15], on a schedule — a semi-annual aerial survey of the coal pile in one utility's 1997 practice [11]. | Periodic — twice a year in that utility's case — and the book adjustment waited on separate boring and density data [11]. |
| Drone photogrammetry | The drone photographs the pile from above and software builds a 3D point cloud or surface model, from which the volume is computed [14][15]. | Battery life on long flights; indoor and concealed storage is harder [14]; flights near airports need airspace authorization [17]. |
The industry standard that names the purpose most plainly is ASTM D6172, a photogrammetric test method for stockpile volume. In its own words it "audits the volume of material in a stockpile and is used with a density value to calculate a tonnage calculation value used to compare the book value to the physical inventory results" [4]. It is worth knowing exactly what it covers: it allows only contour and cross-section methods compiled directly by an operator, and states that creating contours or cross sections with digital terrain model software "is NOT encompassed" [4]. Modern drone software, Omniris included, integrates a gridded surface model instead, which is a different method from the one D6172 describes.
Tons are volume times density, and the density has to be measured separately from the volume.
| Setting | Typical cadence reported |
|---|---|
| State highway agency stockpiles (aggregates, salt, sand) | Traditionally measured yearly because of the labor and time involved — "at best, yearly" in one state DOT, which otherwise guessed at its inventory; with digital measurement, staff measure at any frequency needed [15]. |
| Electric utility coal | Survey adjustments reported to a state commission for the month in which they are booked [10]; a semi-annual aerial survey of a coal pile in one utility's 1997 practice [11]. |
| Annual audit | An annual stock observation of material carried on the balance sheet [13]. |
| Asset-based lending | Field audits often quarterly, more often if risk dictates; weekly or daily in a workout [12]. |
Independent, peer-reviewed head-to-head studies of drone counts against walking surveys are scarce. The figures below are from audit-firm trials and public-agency reports, and are labelled as such.
Walking a pile is the hazard that drones remove. US mine safety rules require surge piles and similar storage of loose material to be handled so that, in normal operations, people do not have to enter or work where they could be trapped by caving or sliding material [16]. State DOTs list blind spots, being struck by or caught between heavy equipment and vehicles, and falls, slips and trips on snow and ice among the hazards staff face when measuring stockpiles [15], and the audit-firm trial named health and safety as a benefit [13].
Each row is one job the industry does with a drone flight, and what Omniris delivers for it.
| Use case | What Omniris delivers |
|---|---|
| Volume of each pile at period end | Draw the boundary on the stitched map; volume integrated from the full-resolution surface model with a ± uncertainty, the no-data share and a bad-boundary warning. |
| Tonnage from volume | Density (preset or your own tested figure), state and swell/shrink factor; each tonnage labelled "preset (nominal)" or "site-tested", so the density's source travels with the number. |
| Recurring counts (month, quarter, year end) | Save the measurement on the site; every later flight that covers it is measured automatically. Hire pilots on a recurring schedule through the marketplace (cloud and data center editions). |
| Site inventory at a glance | The site's inventory card: every pile's latest volume and tonnage, a trend line, and a total of the latest tonnage across the piles. |
| Book-to-physical reconciliation | The physical side of the reconciliation: volumes, tonnages and a spreadsheet of every result, ready to set against the book quantities in your accounting system. |
| Material moved between two dates | Compare two flights over a saved boundary: material added, removed and net, with a grade for how well the two surveys line up. |
| Being told when a pile changes | A change alert on a saved measurement emails you when the net, added or removed volume between flights passes a threshold you set. |
| Pile on a pad, in a bin or against a wall | Six base choices: triangulated, best-fit plane, lowest point, highest point, a known elevation, or a design surface. Base heights can be edited vertex by vertex. |
| Evidence for the auditor | A signed, independently timestamped chain of custody on imagery and maps, measurement history sealed in the same ledger, legal holds, retention, verify page and offline checker. |
| Lender collateral field exam | Read-only access, frozen snapshots and map links on which the examiner can see the piles, open the reports and run their own check measurements. |
| Utility coal pile survey | Volume, tonnage with your tested density, and a monthly series of measured quantities for the survey adjustment to be based on. |
| Map accuracy stated, not assumed | Ground control points and independent checkpoints, with measured horizontal, vertical and 3D error on the delivered map. |
| Asking about the inventory in plain language | Orion, the Omniris assistant, answers from your saved measurements and can work out a volume on a flight; it reports cubic yards first. |
A grid flight with the camera pointing straight down, planned in Omniris or in the pilot's own app. Optional ground control points and checkpoints tie the map to your survey coordinates.
The photos are stitched into a map and a surface model (DSM) at the flight's ground detail. A 3D model run also produces a surface model that the volume tool can read.
Draw it once on the map and save it on the site, with the pile's base method and its material.
Computed at full resolution and stored as a result for that flight. Each later flight that covers the boundary is measured the same way, automatically.
A printable report for any pile and flight, a spreadsheet of every result, and the site's inventory total.
Share read-only, freeze a snapshot, or send a map link; hold the period-end evidence so it cannot change.
Open Map Tools on the stitched map, choose Volume, and draw a polygon around the pile. The guidance in the tool is the single most useful accuracy advice there is: draw the boundary along the bottom edge of the pile, right where the pile meets the ground, and draw it the same way every time. The printed report repeats this advice in its accuracy notes.
The base is the surface the pile is measured above. Omniris offers six, each with plain-language advice in the picker:
| Base | When to use it |
|---|---|
| Triangulated (default) | The base follows the ground under the pile, interpolated from the boundary's own elevations. The right choice almost everywhere. |
| Best-fit plane | Tilted but flat ground, such as a ramp or a sloped pad: one plane fitted through the boundary. |
| Lowest point | A flat pad. The tool warns that one vertex in a rut or shadow drops the whole base and inflates the volume. |
| Highest point | Trenches, ponds and pits: the volume of the hole below the highest edge. |
| Custom elevation | A known floor or bench elevation, typed in feet (or metres). |
| Design surface | A design file (DXF, LandXML or a design GeoTIFF) or an imported design model, for example a storage pad's designed floor. The survey is converted into the design's own coordinate system and heights cell by cell, so a design in feet on a State Plane grid with NAVD88 heights is measured correctly; what a design file doesn't declare (its coordinate system, units or vertical datum) is asked in the volume tool and recorded with the measurement. |
Where the ground under a pile is uneven, or a vertex lands on a truck or a pothole, Edit base elevations per vertex lets you set the base height at individual vertices, and Align vertices to lowest sets them all to the lowest sampled elevation in one click.
Tonnage is the pile's volume times the density, times a swell or shrink factor if you give one. Pick a preset or type your own:
| Preset (nominal) | Density |
|---|---|
| Sand (dry) · Crushed stone · Riprap | 2,697 lb/yd³ (1.60 t/m³) |
| Gravel (loose) | 2,562 lb/yd³ (1.52 t/m³) |
| Topsoil | 2,427 lb/yd³ (1.44 t/m³) |
| Clay (wet) | 3,085 lb/yd³ (1.83 t/m³) |
| Asphalt millings · Demolished concrete | 3,203 lb/yd³ (1.90 t/m³) |
| Coal (bituminous) | 1,433 lb/yd³ (0.85 t/m³) |
| Wood chips | 590 lb/yd³ (0.35 t/m³) |
Presets are handbook figures and are labelled preset (nominal) wherever the tonnage appears. Salt, fertilizer, clinker, cement raw materials, biomass and scrap have no preset: enter the site's own figure and choose site-tested, and the label follows the number into the panel, the report, the inventory card and the spreadsheet. You also record the material's state (bank, loose or compacted). With imperial units, density is entered and shown in pounds per cubic yard with metric tons per cubic metre in parentheses; with metric units, in t/m³. It is stored in t/m³, so changing your units never changes a saved measurement. 1 t/m³ is 1,685.6 lb/yd³ (about 62.4 lb/ft³, or 0.843 US tons per yd³).
On screen, volumes show in cubic yards and tonnage in US (short) tons when your preference is imperial; the printed report always shows both unit systems, imperial first with metric in parentheses, because it is read by people whose preference nobody knows.
Save a measurement on a site and it becomes a standing question: how much is inside this boundary now? Omniris answers it for every flight of that site that covers the whole boundary, including flights that arrive later, without anyone pressing a button. A flight that clips only a corner of the pile is not used, because its number would look like the pile shrank. If you edit the boundary, base or material, every past result is recomputed in the background, so the series always reflects the current definition. The earlier figures are not lost: the edit records the old and new value of each setting it changed, and every recomputed flight records the volumes and tonnage it had before alongside the new ones, in the measurement's custody record. The series on screen shows only the current figures.
For any saved measurement, Compare two flights to get the material added, removed and net between them, with a difference heat map on the map. Each comparison carries a grade for how well the two surveys line up: green when their surfaces agree to 1.6 ft (0.5 m) or better, amber to 6.6 ft (2.0 m), red beyond; a pair with no ground control or alignment is still computed but labelled an estimate. A change alert on the measurement emails you when the net, added or removed volume between the newest flight and the one before passes a threshold you choose.
Orion, the Omniris assistant, can answer questions such as "what was the north yard coal pile on the last flight?" from your saved measurements and their recorded results, compare a saved measurement between two flights, or work out a volume for a site zone on a flight. It reports cubic yards first, says when part of the boundary had no data, and sees exactly what you can see. See the Orion paper.
Three things decide how good a tonnage is: the surface model, the boundary and base, and the density. Omniris is explicit about each, and about which of them it controls.
A single pile's volume on a single flight depends on relative accuracy: whether the map is true to itself. Comparing two flights, or measuring against a design, depends on absolute accuracy: whether the map sits where a surveyor would put it. The volume tool and the report say this in so many words, and a comparison of two flights that were neither controlled by the same set of ground control points nor aligned one to the other is labelled an estimate. Within a single period-end count, the plus-or-minus and the no-data share are the numbers to read; across periods, the alignment grade.
Where a count must be tied to survey coordinates, Omniris supports the full ground-control workflow: import surveyed points from common survey instruments and software, mark them in the photos (printed coded targets are found automatically), and review each point's fit after the stitch. Points can be used as checkpoints instead: surveyed points left out of the fit and used only to measure it. The results give each checkpoint's error east, north and up and the horizontal, vertical and 3D RMSE on the delivered map, and checkpoints marked later can be measured on the finished map without re-stitching. After a stitch with control, the results state an accuracy class set by the least accurate control point used. Details are in the Stitching paper.
A drone measures shape. The density that turns cubic yards into tons comes from your site's testing program or a handbook value, and the published methods for it (ASTM C29/C29M for aggregate [6], ASTM D6347/D6347M for coal in the pile [5]) are field and laboratory work. Omniris records which you used, labels it on every number, and recomputes the whole series if you change it, with the change recorded.
| Reference | What it is | How it relates to Omniris |
|---|---|---|
| PCAOB AS 2510 [1] | Auditor's procedures for inventories, including observing counts. | Omniris gives the company and the auditor a measurement and its record. Whether and how the auditor relies on it is the auditor's judgment. |
| PCAOB AS 1105 / AS 1210 [2][3] | Evaluating the work of a company's specialist and of an auditor-engaged specialist. | The provenance block, custody record and independent checkpoints are the kind of information such an evaluation looks at. Omniris is not itself a specialist and gives no opinion. |
| ASTM D6172/D6172M [4] | Stockpile volume by operator-compiled photogrammetric contours or cross sections. | A different method: Omniris integrates a gridded surface model, which the standard says it does not cover. |
| ASTM C29/C29M [6], ASTM D6347/D6347M [5] | Bulk density of aggregate; in-pile bulk density of coal. | Field and laboratory methods. A density obtained this way is entered in Omniris and labelled site-tested. |
| 18 CFR Part 101, accounts 151 and 501 [9] | Utility accounting for fuel stock and fuel used. | Omniris supplies the physical quantity a survey adjustment is based on. The accounting entries are the utility's. |
A drone volume from Omniris is a measurement made from photographs, not a survey signed by a licensed professional. Where a contract, a lender or a regulator requires a licensed surveyor's certification, the surveyor can use Omniris's data and checkpoint results as an input, and the certification remains theirs.
An auditor relying on a count, or a lender testing collateral, needs to know more than the number: where the data came from, who handled it, how the number was produced, and that none of it changed afterwards. Omniris keeps that record as a matter of course, using the same machinery described in the Evidence Integrity paper.
| Link in the chain | What Omniris records |
|---|---|
| The flight's photos | Each file's SHA-256 fingerprint and its complete chain of custody from upload: who uploaded, viewed, downloaded, shared, moved or processed it, and when. |
| The orthomosaic and surface model | Processing results are files in your vault with their own fingerprints and custody history, starting when they were produced. The stitch report states the control used, the accuracy class and any checkpoint results. |
| The measurement | Creating, editing, deleting and evaluating a saved measurement are each sealed into the custody ledger, with who acted and when; an edit records which parts of the definition changed (the boundary, base, material and so on) with the old and new value of each, and each evaluation against a flight records the volumes it computed; the recompute that follows an edit records, for every flight it replaces, the volumes and tonnage before and after, then a summary of the whole recompute. |
| The result | Stored per flight with the definition it was computed under: surface, base and its parameters, density and its label, ground detail, no-data share and warnings. The report prints exactly that stored result. |
| The hand-over | Sharing codes, public links, and every view and download through a link are written into each file's custody history. |
Every custody event is sealed into a ledger that can only be added to. Each hour, or immediately when a certificate is requested, new events are combined into a Merkle tree; the resulting anchor is linked to the one before it, signed with the deployment's own key, and timestamped by an independent public timestamp authority under RFC 3161 (DigiCert, with Sectigo as a fallback). Changing, removing or reordering an event afterwards breaks a fingerprint that has already been signed and timestamped. Each deployment re-checks its own ledger every day, recomputing it in full every week, and alerts the people who run it if anything no longer matches.
A file certificate covers one file's complete custody history; a folder manifest covers every file in a folder and its subfolders (up to 2,000) with each one's latest proven event and fingerprints, a natural fit for a period-end flight folder. Certificates are signed PDFs (PAdES) carrying their own proof, and can be checked three ways:
Certificates are issued for files, folders, findings and retention disposals. A volume measurement's history is sealed in the ledger and its inputs carry file certificates; the printed report itself is a page you save. To give the period-end report its own fingerprint and custody history, upload the saved PDF to the period-end folder, where it is recorded like any other file and can be certified. A hold protects files and job records; a measurement definition stays editable, with every change kept on the record.
There are two ways to get the flights: your own team, or pilots hired through Omniris.
An organization is a company account with one shared vault. Managers create jobs and assign pilots; pilots can upload into the folders of their jobs; viewers see only the folders a manager grants, which suits a controller or an internal auditor who needs to look but not change. Sites in Site Manager hold the yard's boundary, its saved measurements and every flight over it. See the Site Management paper.
On the Omniris cloud and the data center edition, a client posts a job: nearby approved pilots are notified, or the client offers it first to a pilot who has completed work for them before (if that pilot declines or does not answer in time, it opens to the marketplace), or hires a pilot organization. A job can be recurring: weekly, every two weeks, monthly, quarterly, or a custom "every N days, weeks or months", with each occurrence created on schedule and landing on the same day of the month for monthly and quarterly cycles. The pilot delivers results straight into the client's vault as a read-only snapshot; downloads unlock when the client accepts. The marketplace, payments and invoicing are not part of on-premises installations.
For a volume count, a grid flight with the camera pointing straight down is the pattern to use; a perimeter pattern with the camera facing inward is offered for tall piles and structures. The planner works out height, overlap, photo count, time and batteries from the pilot's own aircraft and camera, can follow the terrain, enforces no-fly areas drawn on the job, and exports a mission file for the pilot's flight app. See the Mission Planning paper.
A port, terminal or power station near an airport may sit in controlled airspace. Under FAA Part 107, flights in Class B, C or D airspace, or the surface area of Class E, need prior authorization from air traffic control [17]. Omniris checks the whole route against FAA airspace and the UAS Facility Map, says whether LAANC authorization is needed and at what ceiling, and prepares a ready-to-paste block of details to file in any LAANC app. Pre-flight checklists and flight logs are kept with the job. On the ground, the point is that nobody walks the pile [15][16].
The people who rely on a count usually sit outside the company that made it. Omniris gives them access that matches their role, and records it. The full detail is in the Sharing and Delivery paper.
| Way to share | What the recipient gets | Good for |
|---|---|---|
| Sharing code, Read Only | Another Omniris account opens the folder from its own login and can view and download, but not change anything. | An audit firm or lender with its own Omniris account. |
| Sharing code, Snapshot | A frozen, read-only copy of the folder as it was when the recipient redeemed the code, in the recipient's own vault, with its own custody history for each copy. | The period-end record: exactly what was handed over, on that day. |
| Organization viewer | Read-only access to only the folders a manager grants. | Internal audit, the controller's team. |
| Site Navigator link | A web link, no account needed, to the site's map with the dates and layers you choose. Optional password, expiry and access level. | An external auditor's or examiner's own look at the piles (below). |
| Public folder link | A folder in any browser, view-only or view-and-download, with optional password and expiry. | Sending the period-end folder: photos, maps, reports. |
A Site Navigator link that includes an elevation layer also shares that site's saved measurements on the shared dates. The recipient can open each measurement's results and its printed report, export the spreadsheet, and draw a boundary of their own to run a check measurement on the full-resolution data. Nothing they do is saved into your account. On a view-and-download link they can also download the shared maps, including the surface model, so their own specialist can recompute the volume independently in other software. Every download through a link is written into the file's custody history before it is sent, and each shared map or file a recipient opens is recorded there as a view. Heavier tools on a link, such as volume calculations, have an hourly allowance per link.
Protected (encrypted) maps cannot be put on a Site Navigator link; share those with a sharing code instead.
Omniris runs in four ways, and the volume tools, saved measurements, inventory card, reports, custody ledger, certificates, legal holds and retention work the same in each:
| Deployment | Where it runs | Notes for inventory work |
|---|---|---|
| Omniris cloud on Microsoft Azure | Omniris-operated, in Azure | Signing key held in Azure Key Vault; locked escrow storage for held evidence. Marketplace available. |
| Omniris cloud on Google Cloud | Omniris-operated, in Google Cloud | Signing key held in Cloud KMS; locked escrow storage. Marketplace available. |
| Data center edition | Omniris's own data center | Signing key in the server's TPM security chip or a protected key file; write-once escrow storage. Marketplace available. |
| On-premises | Your own servers | Stitching, volumes and custody run on your hardware. Commerce (marketplace, payments, invoicing) is off; flights are flown by your own team. Anchors made while a site cannot reach a timestamp authority are still signed, and are covered by the first timestamp obtained once it reconnects. |
Security, encryption and access control in each deployment are covered in the Security paper.
A tonnage is only as useful as the claims made for it. Omniris states its boundaries where they apply:
Industry statements in this paper cite the sources below. Figures from audit-firm trials and public-agency reports are labelled as such in the text.