Cut/Fill Heat Map

The Cut/Fill Heat Map generates a colour-coded raster overlay on the CesiumJS map showing the difference between your survey DEM and a design surface across the entire overlapping area. It provides a visual overview of earthworks progress without needing to draw individual measurement boundaries.

What the Heat Map Shows

The heat map compares two surfaces pixel by pixel:

• Survey DEM — the current terrain surface from your processed drone survey
• Design surface — the target finished level from an uploaded DXF or KML file

At each point, the difference is calculated (survey elevation minus design elevation) and assigned a colour:

The intensity of the colour corresponds to the magnitude of the difference. Deep red indicates large cut requirements; deep blue indicates large fill requirements.

Generating a Heat Map

Step 1: Select the Design Surface

From the Design Comparison tools, choose Cut/Fill Heat Map and select the design surface you want to compare against. The dropdown lists all design surfaces uploaded to the current site.

Step 2: Configure Options

Before generating, you can adjust:

• Resolution — controls the pixel size of the output raster. Higher resolution gives finer detail but takes longer to generate. Options typically range from 0.1 metres to 2 metres per pixel.
• Colour scale range — set the minimum and maximum difference values for the colour scale. Points beyond these limits are shown at full intensity.

Step 3: Generate

Click Generate Heat Map. SiteView calculates the difference grid and renders the result as a raster overlay on the CesiumJS map.

ℹ️ Did you know?

Generation time depends on the area size and resolution. A small site at 0.5m resolution may take a few seconds. A large site at 0.1m resolution can take a minute or more. A progress indicator shows the status during generation.

The Legend

A legend panel displays alongside the heat map showing:

• The colour scale from maximum cut (deep red) through neutral (white) to maximum fill (deep blue)
• The numeric values corresponding to each end of the scale
• The resolution used for the calculation

The legend helps you interpret the colours and understand the magnitude of differences at any point on the map.

Interacting with the Heat Map

Opacity Control

Use the opacity slider to adjust the transparency of the heat map overlay. This lets you see the underlying survey imagery or terrain through the heat map, which helps with spatial orientation.

Click to Query

Click any point on the heat map to see the exact values at that location:

• Survey elevation
• Design elevation
• Difference (in metres and millimetres)

This gives you precise data at specific points without needing to run a separate Grade Check.

Toggle Visibility

Use the Layers tab to toggle the heat map on and off. This is useful for switching between the heat map view and the raw survey imagery.

💡 Tip

Overlay the heat map at reduced opacity on top of the orthophoto. This lets you see the cut/fill colours while still being able to identify physical features on site, making it easier to communicate progress to project stakeholders.

Use Case: Visual Earthworks Overview

The heat map is ideal for:

• Progress meetings — show stakeholders where earthworks are complete (neutral areas) versus where work remains (coloured areas)
• Bulk earthworks planning — identify which zones need the most cut or fill before mobilising equipment
• Completeness checks — quickly scan for areas that may have been missed or under-cut
• Time-lapse comparison — generate heat maps from successive survey dates and compare the changing colour patterns

⚠️ Watch out!

The heat map provides a visual overview rather than precise quantities. For accurate volume calculations, use Compare to Design Volume with a defined polygon boundary. The heat map colours represent relative differences and are best used for spatial understanding, not for payment or quantity claims.

Performance Considerations

Heat map generation is computationally intensive. A few factors affect performance:

• Area size — larger sites produce larger raster grids
• Resolution — finer resolution creates many more pixels to calculate
• DEM quality — higher-resolution DEMs provide more accurate results but take longer

For very large sites, consider starting with a coarser resolution (1m or 2m) for a quick overview, then regenerating at finer resolution for specific zones of interest.

What's Next?

• Compare to Design Volume — calculate precise cut and fill volumes within a polygon boundary
• Grade Check vs Design — check individual point elevations against the design
• Cross-Section vs Design — visualise the profile difference along a section line
• Survey Layers & Overlays — manage survey data layers on the globe