How to Create a Surface Comparison

Comparing surfaces and creating volume measurements are key components to effectively analyze your site. The Surface Comparison tool allows you to designate an area using the polygon tool, and then compare drone surveys, design files, and a variety of other surfaces in the platform. 

Use cases 

  • Measure stockpiled material on an uneven surface using a previous flight, imported design, or interpolated surface as the base
  • Measure earthworks progress
  • Measure landfill cell conformance to design
  • Create dynamic cut/fill or takeoff maps

Types of volume measurements

Basic Volume: Measures the volume of material in a polygon.

Bench Volume: Useful for measuring blast volumes or the volume of a bench or wall section.

Cell Progress: Measures the remaining airspace volume in a cell.

Compare to Design: Measures volume between the selected survey and an uploaded design surface.

Compare to Previous Survey: Measures progress or volume between a selected survey and a previous site survey.

Design to Design: Measures the volume between two designs within a polygon.

Earthwork Progress: Measures site progress since the previous survey and against an uploaded design surface. 

Stockpile: Measures a stockpile using a smart, reference level, or custom base. Use the Stockpile Measurement template to create customized Stockpile Inventory Reports.

Volume from Lowest Point: Measure the volume using a horizontal base plane anchored by the lowest point of your polygon. This is useful when measuring pit walls, benches, and blast volumes.

How to create a measurement

1. From the MEASURE tab, click CREATE A MEASUREMENT.


2. Select a measurement template from the Calculate Volume Section of the Template Picker.


3. Use the Magic Polygon tool or manually draw a polygon around the area you want to measure.


4. If you want to change your template, you can do that from the Template dropdown menu.


5. Select the surfaces you want to compare in the From and To Surface dropdown menus.


How to compare one dataset or design to another

1. From the MEASURE tab, click CREATE A MEASUREMENT.

2. Select Compare to Previous Survey, Design to Design, or Earthwork Progress from the Track Progress section of the Template Picker.

3. Use the Magic Polygon tool or manually draw a polygon around the area you want to measure.

If you choose the Compare to Previous Survey option, the From Surface will already be populated with the previous survey, and the Current Surface will populate the To Surface option.

You can always switch between the From Surface and To Surface comparison calculation by clicking the arrows between the two surfaces.

Suppose you choose the Compare to Previous Survey option. In that case, the surface comparison tool will automatically populate the previous survey in the From Surface field and the current survey in the To Surface field.

When comparing surveys, they must overlap with the current measurement to calculate data.

When comparing surveys, keep in mind the following:

  • When comparing a current dataset to an older dataset, the FILL value is the volume added to the selected area, and the CUT value is the volume that has been removed. If the amount of material in the region has increased, the NET volume is shown as positive. 

  • This can be visualized using a heat map to highlight cut and fill areas, as seen below. The dark red areas are mounds of stockpiled fill flattened in the period between datasets. The blue areas are being filled to reach design level conformance, while uncolored areas have minimal changes in the period between the two datasets.


How do I use the deadband in volume comparison measurements?

Users can set a deadband for their measurements using the volume comparison tool. This deadband will ignore surface changes less than the minimum value set for the heatmap and will not contribute any of those changes to the CUT/FILL/NET/Total values generated for that measurement.

To enable the deadband for your volume comparison measurement, scroll down below the CUT/FILL/NET/Total numbers to the Heatmap section of the measurement, and check the box for Use deadband in the calculation. Then, you must apply that change by clicking APPLY at the bottom of the measurement.


You will see an information box alerting you the deadband has been applied successfully.


As a default for drone survey comparisons, the minimum value is 0.1ft (3 cm) in Imperial units, and 0.1m (10 cm) in Metric units. However, the Deadband is not enabled automatically. 

Using DirtMate data in volume comparison measurements

The deadband of 0.1ft (3 cm) or 0.1m (10 cm) is automatically applied on measurement creation when DirtMate layers are toggled on. If the deadband is not applied, you will see a message with a link to APPLY DEFAULT. Please get in touch with our Site Support team for questions about the deadband when applied to DirtMate measurements.

I still can't do it!

We wrote these articles to equip you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.

If you're stuck, you can connect with our support team by clicking the support button on the top right corner of your user portal.

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