Orienting Goes South

Exploration Stage: Yard of Forgotten Toys
From: Detective
Description: The Collector writes: "The City can open portals." Then he says that he studied where these portals lead and assembled a special compass.\n It may indicate where to look for the Collector! Let’s find the compass.
Completed: It’s a sidewalk compass! I saw one before... but the cardinal directions weren’t changing on it. How can such a strange device help you understand where the portal leads?