How to read the Real-time visitor map in Piwik PRO Analytics module?
Each bubble visible on the screen represents a Visitor. The view is refreshed every 5 seconds, and the new visitors appear on the map with a flashing effect. The bigger and brighter the bubble, the more recent the visit. The older the visit, the smaller and darker the color of the bubble.
Please take a look at our article about Real-time visitor map.