There is no widely recognized term or concept called "radiant drift map." It's possible that this is a specific term used in a particular context, like a game or a software application.

To help me understand what you're looking for, could you please provide more information?

For example:

* Where did you encounter this term? (e.g., a game, a website, a book)

* What is the context of the term? (e.g., a specific game mode, a data visualization tool)

* What do you think it might refer to?

With more context, I can provide you with a more accurate answer.