Thanks for your answer.
In fact this is simple.
The metric I need to symbolize is a field value (ie: rssi: -20 dBm for instance)
Each coordinates point will have a RSSI value associated (each document)
I need to display a heatmap with a range of colors/rssi_value from blue (low value: -140 dBm) to red (hot value: -20 dBm)
This is usual in radio monitoring activity to have a map like this.
Is it clear?
