Geospatial Heatmap
Geospatial heatmap charts are useful for displaying how geographical areas of a map compare to one another based on a given criterion.
Heatmap charts can use a maximum of 10,000 documents. If you create a heatmap with a collection of more than 10,000 documents, turn on Sample Mode or use a filter. Otherwise, your chart may use incomplete or misleading data.
To create a geospatial heatmap chart:
- On the chart editing screen, select Geospatial from the Chart Type dropdown menu.
- Select Heatmap from the three available geospatial chart types.
Geospatial Heatmap Encoding Channels
Coordinates
A geopoint encoding channel which defines the map area of the chart. See the Geopoint reference page for more information about what types of data you can use in this channel.
Intensity
An aggregation encoding channel that changes the shading of the colors in different chart regions to reflect the aggregated values of this field. More intense colors in the visualization reflect greater aggregated values.
The radius customization option dictates the size of the data markers in Geospatial Heatmaps. The color of each data marker reflects the aggregated value of all data points within that marker's radius.
If ten data points exist within the specified radius, the color displayed is based on the aggregated value of those ten data points.
Intensity shading is local to the map's current view. The most intense color is displayed for the most extreme aggregated values currently visible on the map, even if there are points outside the current view that are more extreme.
Legend
Unlike other types of charts, the legend and the chart colors on geospatial heatmaps change when the view changes. The color range is based on the data in the current view, and may change when you pan or zoom the map.
Customization Options
The following customization options are specific to geospatial heatmap charts. For general customization options, see Customize Charts.
Automatically Set Viewport
By default, geospatial charts show a map which includes all the data point markers in your specified collection. You can pan and zoom to change the map view, but if you close the chart and re-open it the map reverts to its default state. This behavior is controlled by the Automatically Set Viewport option.
When you toggle the Automatically Set Viewport switch to
Off, the area and zoom level at which the map is saved becomes the
new default view.
You can pan and zoom the map area in a chart on a dashboard, but these changes do not affect the default map view.
Radius
You can adjust the radius of your data points. The radius is measured
in pixels and defaults to 30.
Opacity
The Opacity level of a map modifies the degree to which the chart's map data shows through the data point markers.
Geospatial heatmap charts default to 100%.
Custom Color Palette
The color palette specifies the range of colors that corresponds to relative aggregated values in your map. Geospatial heatmap charts use a gradient color picker.
To enable palette customization, toggle the Custom Color Palette switch in the General section.
For more information, see Color Palette Customization.
Examples
The following chart is based on AirBnB data for the New York City area. It shows rental rate hot spots in a geospatial heatmap.
The Coordinates channel uses the location database
field, which contains arrays of latitude-longitude pairs. The
Intensity field uses the monthly_price database field,
which contains monthly rental rates for each property in the database.
Limitations
The maximum query response size for a geospatial heatmap is 50000 documents.