The HQ Map is a complicated electronic device, which by necessity detects routes in six dimensions:
As explained by the Daisy:
You move in probability every time you go into an alternate fic-verse. And, to a lesser extent, every time you use a portal. It's the difference between the probability of you being at one end over the other, and the ability to change those probabilities, that make them work.
A move 'backwards' in consciousness, that is, a move towards the unconscious, tends to make the route shorter.
The Map was first revealed to Agent Alex Orange and the Daisy, who tested it (this took place in the second PPC Playscripte). It has not seen much use by the PPC, being well guarded by the Flowers. However, a copy was stolen by Flickerbright of the Black Cats, and rapidly duplicated to the extent that all the Black Cat teams had maps during their invasion. Back when the DIS were still in power, they had access to a simplified copy of the HQ map in Central; this was notably used during the civil war against the rest of the PPC, to monitor and coordinate the fighting.