Thing snapshots

AMTech Platform keeps track of last values of thing properties. Such properties must be configured in the thing type semantic definition as explained here. You need to set the maximum number of snapshots to be stored for the property (observation limit) and the minimum time between two changes to create a new snapshot (observation frequency).

Each time a modification to a thing property is done, it is verified if the last snapshot for this field was done at least the time in observation frequency before. Use 0 to accept all modifications. Also, set the observation limit to say how many snapshots to store. The last ones are removed if the limit is reached. If observation limit is 1 (default), then only the last version is stored and there is no other snapshot for such property.

This feature have two uses in AMTech Platform:

• Timeline view shows the stored snapshots and their modification time. Also the map include the last locations if the field has more than one snapshot.
• Observers allow to define constraints on the snapshots by using their average, minimum, maximum, count or sum.