Heat map
Icon Map Slicer has the ability to create heat maps from point data. The heatmap provides GPU-accelerated rendering and smooth zoom-level interpolation.
Data configuration
To configure the data well for a heatmap, the following fields should be populated:
- ID – A unique ID for that location and item.
- Longitude (with aggregation type Average)
- Latitude (with aggregation type Average)
- Heatmap Weight – The numeric value for that location.
Sample data
| ID | Longitude | Latitude | Destination Longitude | Destination Latitude | Circle Size | Cluster Group | H3 Weight | Heatmap Weight | Image / WKT / GeoJSON | Feature Reference | Feature Weight |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ID1 | -2.576 | 51.481 | null | null | null | null | null | 45 | null | null | null |
| ID2 | -2.576 | 51.481 | null | null | null | null | null | 62 | null | null | null |
| ID3 | -2.955 | 51.332 | null | null | null | null | null | 41 | null | null | null |
| ID4 | -2.155 | 51.632 | null | null | null | null | null | 12 | null | null | null |
Heatmap – Configuration
In the Data Layers card of the formatting options, ensure that "Heatmap" is enabled. This will then show the Heatmap – Configuration and Heatmap – Formatting cards.
Display Min Zoom / Display Max Zoom
Controls the zoom range at which the heatmap layer is visible on the map (0–24).
Radius (Zoomed Out) / Radius (Zoomed In)
Sets the heatmap point radius in pixels at low and high zoom levels. The radius interpolates smoothly between these values as the user zooms.
Advanced Settings
Enabling the Advanced Settings toggle reveals three additional sub-groups for fine-tuning the heatmap behaviour at different zoom levels:
- Heatmap – Weight: Controls how data values are mapped to heatmap weight across zoom levels, with Zoomed Out At and Zoomed In At breakpoints.
- Heatmap – Radius: Provides full control over radius zoom breakpoints and values, with separate Zoomed Out At/Zoomed In At zoom levels and corresponding radius values.
- Heatmap – Intensity: Controls the intensity multiplier across zoom levels, with separate Zoomed Out At/Zoomed In At zoom levels and corresponding intensity values.
Include in Auto Zoom
Whether heatmap points should be included when auto-fitting the map bounds. Supports conditional formatting.
EPSG (Coordinate Reference System)
Specifies the coordinate reference system of your data. The default is 4326 (WGS84 – longitude and latitude). Other EPSG codes can be used, such as 27700 for British National Grid. EPSG codes reference.
Z-Index
Determines the drawing order relative to other layers. Higher numbers are drawn above lower numbers. Note that items below the heatmap layer will not be interactive (i.e. cannot be selected or show tooltips).
Heatmap – Formatting
Transparency
How transparent the heatmap layer is (0 = fully opaque, 100 = fully transparent).
Number of Colors in Gradient
The number of colour stops in the heatmap gradient (2–5).
Color 1–5
Configure up to 5 colours for the heatmap gradient, from lowest density (Color 1) to highest density.