Device Mapping

What is Device Mapping?

Device Mapping is a system that scans and tracks real-world objects, allowing you to place content in alignment with the real world. On the surface, it is functionally similar to VPS, but the Device Mapping system does all its processing on the device and does not require a network connection to localize. Instead, Device Mapping serializes a scan from one client device and distributes it to the others, which then deserialize the data and recreate the scanned map. This allows multiple devices to share a map and play a multiplayer experience without an Internet connection.

For a better idea of how Device Mapping works, compare it to VPS:

	VPS	Device Mapping
Where can you use it?	VPS-Activated Locations Only	Anywhere
How is the map built?	Using scans from many users at different times	A single scan
Do you need to scan to use the map?	No	Yes
Do you need network connection to localize?	Yes	No
Where does the map data live?	Niantic servers	Your device
Localization robustness	Consistent because it generates the map from multiple scans	Robustness depends on the quality of the single scan
How to access associated visual data	Download mesh from the internet	Extract point cloud from device map data

High-Level API Overview

At a high level, the Device Mapping API follows these steps:

• Mapping
  • Using ARDeviceMappingManager, scan and generate a device map.
  • Using ARDeviceMap, save the serialized device map data somewhere, such as the device's local file system.
• Tracking
  • Using ARDeviceMap again, restore a device map from the serialized map data on the device.
  • Using ARPersistentAnchorManager, track the scanned real-world data by setting the device map via the ARDeviceMappingManager.
  • Once the device has achieved tracking, populate the virtual objects under ARPersistentAnchor to show them aligned to the real world.

Once StopMapping() is called and the final map is generated, the ARDeviceMappingManager.DeviceMapFinalized event triggers, allowing ARDeviceMap to serialize the map data. ARDeviceMap also provides the necessary API to restore this map data later on. Optionally, you can also show the user the coverage of the device map by listening to the ARDeviceMappingManager.DeviceMapUpdated event and receiving additional device map data that allows you to do so.

Limitations

Device Mapping is subject to some of the same localization limitations as VPS, such as:

• Visual conditions (lighting, weather, time of day) changing between mapping and localization
• Mapped areas with few distinguishing features (such as grassy fields or indoor areas with little difference in color)
• Scans taken from a limited viewing angle

Without the robustness of generating the map from multiple scans, Device Mapping may perform worse than VPS if these limitations come into play. If your multiplayer experience depends on an area that changes regularly or lacks distinguishing features, consider using VPS instead.

Next Steps

To get started using Device Mapping, see How to Create a Device Map.