Download: https://raw.githubusercontent.com/Jormund/import-heatmap/master/import-heatmap.user.js
"Import heatmap" button in toolbox, below portail details opens a dialog.
Import CSV with Import button.
Activate layer in IITC Layer menu (top right)
Sample CSV:
48.944497;2.324291;1
48.94392;2.324923;1
48.945085;2.324411;1
Location: https://intel.ingress.com/?pll=48.944497,2.324291
Result:
