P.S full code at bottom of page
1. Sensor (Obligatory)
Sensor can be either set to true or false to inform the API if the maps are being accessed from a device with location such as a smart phone or not such as a desktop.
If the sensor parameter is not passed, the API will return a “Request Denied” error.
When references Google API, we are still not loading everything. Therefore, we can load these libraries using parameters in the URL. The Visualization library is required when we want to visualize some sort of data using markers, heat maps, or circle size maps.