Intersecting veins of the city

Exploration Stage: Atelier Delamode
From: Lucas
Description: This living city is helping us to find the artifacts that wanderers are supposed to protect. I found a number that seems to point to a house or street. I wish I had a clue as to what this means. If we look around, the city may give us other maps.
Completed: Did you find the strange map on the key chain? Yes, I had seen one myself when Sheriff Keira came to see my sister. But since Keira never loses things, this must be a duplicate of the key chain the town sent me. Here is the street! This is where I should find the house with the numbers on it!