Using this plugin you can easily create heat map (also called choropleth map). You can set a light and dark color, and if your areas/countries/states have values assigned, the map will automatically choose intermediate color corresponding its value.
Below we have built a map with the US population for each state.
The first thing to do is enable the Heatmap option for your map, in the regions or markers tab.
Heatmap options for regions
For the regions, you’ll have to choose the color for the lower values and the colour for the higher values. You’ll also be able to add the text labels that display in the legend, if you want to enable it.
Heatmap options for markers
For the markers, you’ll have the option to add the colour and size for the lower and higher values. You can also choose to enable or disable the legend and add the text labels to it.
Notice on the screenshots above, the last field is the ‘Source field ID’. Depending on how you’re going to add data to the map, you may or may not have to change this. By default, we will look for information in the value field of each entry. If you’re using an external JSON to populate the map, it can be any of the available properties in your JSON file.
With this option enabled, you can add values in 2 different ways.
Add values manually
When adding information for each region or marker on your map, each one has the ‘value’ field, which should have a numeric value. This value will be compared against the others and used to choose the colour (and size) of your region or marker. Remember: it needs to be a numeric value.
Video on how to add the data manually
Add values automatically
You can use this feature in combination with the option to use a Custom Data Source for your map. This can be CSV data or JSON data for example.
For the example map above, we used the ‘Raw Data Content – CSV’ option and added the values available here.
This will automatically add the 4th value in the CSV as the value to be used by the heatmap.
Future versions of the plugin will allow for more custom data sources.
When using the CSV as an external data source, make sure to include all 5 columns. It will only work if you have all 5, color code included, even if the heatmap rules will then replace it.
When using an external data source like the example above, consider that any entry for the same regions added manually will override the entries from the CSV source.
Avoid using transparency in your minimum and maximum colours. The transparency won’t help understanding the different shades of colours.