# Coordinate system and origin across multiple gateways/rooms

Hello everyone,

I have a question about installation and how the coordinate system would work across multiple gateways.

If I have multiple rooms and a separate gateway in each room how will the coordinates change if a tag moves from one room to the next? Is it set up so there is just one origin for all the rooms (so all coordinates will be relative to that), or can there be a separate origin and coordinates for each room? Is there a way this needs to be set up or does it depend solely on how the anchor positioning is defined?

The reason I’m asking is I want to potentially accommodate installing this over 2 floors, with a separate gateway on each floor, and with it’s own (x,y) coordinate system. Each floor could potentially be above each other (so 2 tags could potentially have the same coordinates but be on different floors), but I would need to know which floor a tag is on. What would be the best way to achieve this? I am using MQTT to get the tag location, but it only has x,y,z location. How could I determine the floor?

One idea was to define the anchors as having different Positioning offsets for different floors. For example, on floor 1 the anchors could all be offset (in metres) by (0,0), and thus the coordinates returned for the tags would also be offset by this, and on floor 2 the anchors could be offset by (100,100), and so the tag coordinates would also be offset by (100,100). As long as the respective anchors on each floor have their positioning defined in line with this, I could then determine from the coordinates of a tag which floor it was on. For example, if tag A returned location (5, 5), I would know that it was on floor 1 - on the other hand, if tag A returned location (105, 105), which is actually the same coordinate (5,5), I would know that it was on floor 2.

Would this work? Or is there a better way to do this?

Any help really appreciated.

Thank you.

Sunny