Geotag is a command line tool for adding GPS metadata to jpg images. The GPS metadata is extracted from Google's history and is then matched to the timestamp of the photo using a highly sophisticated algorithm.
During my travels in Australia and SE Asia I wished that my camera has GPS tracker, as it would make later grouping and tagging much easier. I also learned that Google extracts and tracks the location of my phone via the Timeline project. So I decided to use that information and augment my photo collection with the GPS coordinates. This project tries to automate the process.
You'll need to install exiftool before you can use geotag. To do so download and install this dmg. Exiftool is the tool for managing jpg (exif) metadata.
You'll also need to download your google timeline history. To do so, go to takeout, select "Location History (json)", and download the archive to your computer. You'll later need to tell geotag the location of this archive.