Extract Images from icondatapack files
Icondatapack files are found in your ~/Library/Caches/GeoServices folder. They can use 200 MB of disk space, maybe more.
They are used by Apple applications like Apple Maps, and you will find the icons stored inside used in route plans.
File Juicer will extract the PNG files found inside the RegionalResources subfolder. They are mostly icons for local transit so you can recognize the logos should you be in unfamiliar places.
The icondatapack files are also used by Siri, and an Apple background app called "routined" - which in Apples brief explanation is "A daemon that learns the historical location patterns of a user."