Clarify definition of event_interval, use event_ throughout #4

Closed niconoe closed 3 years ago

In GitLab by @peterdesmet on Aug 7, 2020, 10:05

The package property event_interval is defined as:

Maximum interval between sub-sequent observations which are considered as one independent observation i.e. an event. Specified in seconds.

I find it difficult to wrap my head around this definition. Is it the maximum time between two images that are considered to be part of the same sequence? So if set to 30 seconds, then images A (20:30:00), B (20:30:15), C (20:32:00) would be considered as 2 sequences: A+B and C? If so, then that is what we call in Agouti sequence_cutoff.
Can we change the name to something like sequence_cutoff? I find that clearer to understand.

In GitLab by @kbubnicki on Aug 27, 2020, 00:22

I can not agree here. The term event is quite common in camera trapping literature, see e.g. Meek et al. 2014:

The term ‘‘event’’ typically refers to the presence of an animal, on a single occasion in a
location, as detected by a sensor and documented by a camera. Two factors can determine
the precise definition of a camera trap event and should be clarified by the investigators:
independence interval between successive images or sequences of consecutive images (i.e.
video or pseudo video) initiated by a trigger. Although the optimal independence interval
has never been empirically estimated from camera traps, it typically ranges from 10 to
60 min (although 1–5 min has been used for small mammals), and the researcher should
report on the criteria used to set the interval.

So if set to 30 seconds, then images A (20:30:00), B (20:30:15), C (20:32:00) would be considered as 2 sequences: A+B and C? -> Yes!

But I find the term sequence_cutoff much more confusing.

In GitLab by @peterdesmet on Aug 27, 2020, 10:26

I agree that the term event is quite common for biological data (also used in Darwin Core).

Question: do we consider event and sequence to be different names for the same concept?

If so, then I think we should use the same term consistently:

Either mention the word sequence in the definition of event_interval
Or rename sequence to event in media and obs: event_id, event_start, event_end.

If not, can you clarify the difference between event and sequence?

In GitLab by @kbubnicki on Aug 28, 2020, 12:09

Good question. I would say that event is an actual observation i.e. a data point whereas sequence is more a technical/grouping term for a consecutive set of images recorded at one time. But what actually matters in the end is event. The question is if we need both terms or not (if so this can be confusing). I would opt for keeping only event.

In TRAPPER we use only event which is actually named sequence :)

In GitLab by @peterdesmet on Aug 28, 2020, 12:35

@yliefting, @milotictanja could you agree with the terminology that we organize media (and related observations) in events rather than sequences?

In GitLab by @yliefting on Aug 28, 2020, 13:06

The main reason we use the term sequence in Agouti is that it, like @kbubnicki already said, is just a simple grouping of images based on the difference in timestamps. Event implies that it is a data point with meaning. Theoretically a sequence can have multiple events, described in several observations. Since there are large differences between project protocols we chose to stick with sequences and leave any interpretation to the users.

That said, I have no objections to using the term event in the standard. We can simply map Agouti's sequences as events.

One remark: in Agouti videos are always mapped as one video equals one sequence The analogy here is that a video is a sequence of frames, and photos taken in bursts are similar.

In GitLab by @kbubnicki on Aug 28, 2020, 13:20

Ok, thanks @yliefting! This is all so confusing as theoretically one event can also have multiple sequences :) One question: is the time interval to build sequences (sequence_cutoff?) user-defined in Agouti?

In GitLab by @yliefting on Aug 28, 2020, 14:14

Haha, you're right. Good thing we are working on this standard. ;)

The sequence cutoff in Agouti is defined by the project owner at the project level and can vary. The default is 120 seconds, but some projects deviate because they have specific requirements.

In GitLab by @peterdesmet on Aug 28, 2020, 14:17

Do we have a consensus of generalizing the term sequence to event? Thumbs up if you agree, otherwise please continue discussion. :smiley:

In GitLab by @peterdesmet on Aug 31, 2020, 17:19

mentioned in commit b172b07589fa560eb9245be3007fea3badb3c6db

In GitLab by @peterdesmet on Aug 31, 2020, 17:26

mentioned in merge request !4

In GitLab by @kbubnicki on Sep 2, 2020, 14:20

I think that this one we can also close now.

In GitLab by @peterdesmet on Sep 2, 2020, 15:46

changed title from Clarify definition of event_interval to Clarify definition of eventinterval{+, use event throughout+}

In GitLab by @peterdesmet on Sep 2, 2020, 15:47

assigned to @peterdesmet and unassigned @kbubnicki

In GitLab by @peterdesmet on Sep 2, 2020, 15:48

Consensus: all sequence_ proposed terms should be event_. The definition of event_interval could be clarified a bit further, will take a stab at this.

In GitLab by @peterdesmet on Sep 2, 2020, 17:00

My proposal for event_interval:

Maximum number of seconds between timestamps of successive multimedia files to be considered part of a single independent event/occasion and be assigned the same event_id.

Note: I still find the word event_interval a bit confusing, as it seems to be the interval between events. Maybe event_media_interval?

I would also update event_id to reflect :

A unique identifier of an event within a project. Events contain one or more multimedia files (e.g. a single video or a sequence of successive images) and are defined by event_media_interval in the package metadata.

Note: successive vs consecutive (1,2,4 is successive, not consecutive, while 1,2,3 is both)

Updated from:

A unique identifier of an event within a project. Events are what project researchers or software have defined as independent occasions, containing one or more multimedia files (e.g. a single video or a sequence of consecutive images).

In GitLab by @kbubnicki on Sep 2, 2020, 17:13

Already cited Meek et al. 2014 used a term independence interval. I have no idea now, so maybe again lets just keep event_interval and ask the community afterwards?

In GitLab by @peterdesmet on Sep 2, 2020, 20:00

Ok.

In GitLab by @kbubnicki on Sep 3, 2020, 00:41

mentioned in commit 1cf8d960d276ce21e6b3f2f75e918b241f04545d

In GitLab by @kbubnicki on Sep 3, 2020, 00:46

mentioned in merge request !9

In GitLab by @peterdesmet on Sep 4, 2020, 13:31

Implemented in !9.

tdwg / camtrap-dp

Clarify definition of event_interval, use event_ throughout #4