Multi-layer Charts
You can superimpose multiple Pointmap, Linemap, and Geo Heatmap charts on one another to look for correlations between datasets.
To create a multi-layer chart:
- Create a Pointmap or Geo Heatmap chart.
- Click the Add Layer tab.
- Create a Pointmap or Geo Heatmap chart in the new layer.
- Click the Master tab.
- Adjust the Opacity of the chart layers using the sliders on the right.
You can change the order of the layers by dragging the contents of a layer field on top of another layer field.
The limit is eight layers in a single chart, up to your server’s memory and processing capacity.
Multi-layer Chart Example
Create a new Pointmap. For the Data Source, use the official database of UFO sightings.
Set the Lon measure to longitude and Lat measure to latitude. Set the Size measure to duration_seconds. Set the Color measure to shape.
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Click the Add Layer tab, and create a Geo Heatmap. Set the data source to the Flights database. Set Lon to origin_lon and Lat to origin_lat. Set the Color measure to depdelay.
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The resulting chart compares a Geo Heatmap of flight departure delays to a Pointmap of UFO sightings.
Click the Master tab, and reduce the opacity of the UFOs Sighted chart to enhance the visibility of the Flight delay information.
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Clearly, some flights have been delayed where UFOs have been sighted, making it impossible to make a definitive statement that there is no correlation between the two datasets. Spooky.