How to measure traffic coming from Google My Business?

There is currently no default source for Google My Business links.
Indeed, Google indicates the same referrer (parameter that determines the source of the visit) for traffic coming from the classic Google search engine, as for traffic coming from My Business links.
To measure the number of visitors coming from your Google My Business link, we suggest that you enter your website URL with a campaign parameter (whether natural or marketing).
Organic source: http://www.mysite.com/?origin=googlemybusiness (requires the creation of a source group based on origin=googlemybusiness)
Marketing source: http://www.mysite.com/?at_medium=googlemybusiness&at_campaign=googlemybusiness
You can find more information on campaign tracking in this documentation:Marketing campaigns | Piano Analytics Developers Documentation