What it is: a view of your project in context with other efforts underway

When to use it:

When you want to know who else to inform, to collaborate with
When there is a lot of work going on and you don’t want designers to be doing overlapping work (or developers make changes that will have an unintended knock-on effect)

How to use it:

Map out a generic user flow that captures your project’s scope
Add projects as you come across them - current or future planned work
Try getting a sense of how your project relates to this other work - this will let you know what type of involvement you need

This works great with

Service blueprints - service blueprints gives you a cross-section snapshot of your flow and who is involved in making it happen. The cross-project view gives you a way to catch which of those back-end processes you need to pay attention to
Experience impact mapping - when you want to see what projects should be underway