A volume measurement is a polygon that Birdi calculates against your elevation layer (DEM) to give you cut, fill and net volumes. You can draw one with the Volume toggle while drawing, or create a volumetric folder and draw your polygons inside it.
Measure stockpiles, pits, trenches and earthworks
Calculate cut, fill and net volumes against any DEM in your map
Add a material to report tonnage alongside cubic metres
Edit a shape later, and its volume is recalculated with the same settings
What you need: At least one DEM (DSM or DTM) in your map, either processed in Birdi or uploaded.
When to use a volume measurement
Running a stockpile count or month-end inventory
Checking cut and fill on an earthworks site
Measuring material moved between two surveys
Turning AI Detect stockpile outlines into volumes and tonnage
Step-by-step: creating a volume measurement
1. Open your map
Open the map with the survey you want to measure. Make sure it has a DEM.
Tip: Turn off the orthomosaic and turn on a hillshade. Pile edges and changes in slope are much easier to see.
2. Choose a polygon tool
Open the Annotations menu in the toolbar and choose Polygon (P) or Free Draw
(Shift + P).
3. Turn on Volume
In the nav bar, turn on the Volume toggle, or press ⇧V. The shapes you draw are now volume measurements.
The volumetric toggle will create a folder for your annotations or add new annotations to an existing folder.
4. Draw around your area
Click around the edge of the stockpile or area, or trace it with Free Draw. To finish, double-click, right-click or press Enter.
The polygon tool stays on, so you can draw the next stockpile straight away. Press Esc when you’re done.
Tip: Draw along the toe of the pile, where it meets the ground. That’s the edge the base surface is built from.
5. Open the volume panel
Select your volume measurement in the Layers panel or on the map. The Volumetric Layer Toolbox opens.
Tip: To calculate several stockpiles at once, Shift-click them, or hold Shift and drag a box over them on the map.
6. Choose your DEM and base method
Volume DEM: choose the elevation layer to calculate against. A warning shows if you choose the wrong type of layer.
Base method: choose how Birdi builds the ground surface under the pile:
Linear Fit: fits a plane to the points around the edge of your polygon
Lowest Point: sets a flat base at the lowest point in your polygon. Best for flat ground.
7. Calculate
Click Calculate. After a moment, you’ll see:
Cut volume: material above the base surface
Fill volume: space below the base surface that would need filling
Net volume: cut minus fill
The volume label appears on the map.
8. Add a material (optional)
To report tonnage, choose a Material from the library, or choose Custom… to enter your own name and density (t/m³). Tonnage appears straight away, with no need to calculate again.
Changing a volume measurement
To adjust the outline, press E to open edit mode, then drag, add or remove points. You can also use Cut to split one outline into two piles, or Merge to join two outlines into one.
When you save the edit, Birdi recalculates the volume with the same DEM and base method.
See How to edit annotations in Birdi] and [How to cut, merge, simplify and subtract annotations in Birdi
Good to know: There’s no Undo. Cut, Merge and Subtract can delete shapes when you click Apply, so check the list in the panel first.
Best practice tips
Use the DEM from the same survey as your orthomosaic.
Draw tight to the toe of the pile, and avoid nearby piles, walls and vehicles.
Name each volume by material or location so your Table View and reports make sense to others.
Shift-select piles of the same product to calculate them and add their material in one go.
Check volumes against field measurements where precision is critical.