Annotation's layer immutable

[Hila Reicher]

Hi Team,

What's the rational behind defining the layer of an annotation as immutable? 

Is it just a technical limitation of the dashboard or more of a conceptual decision?

We find that having to first select a layer before marking the text makes the annotation process quite cumbersome . 

Would to get you input on this UX decision,

Thanks! 

[Richard Eckart de Castilho]

Hi

A long long time ago in a predecessor to INCEpTION, it was possible to change the layer of an annotation after creating it.

So at that time, a user could create an annotation. After creating the annotation, the user could change the layer of the
annotation through the layer dropdown.

However, changing the layer of an annotation is a destructive action which basically boils down to deleting the current
annotation and creating an annotation of the other layer at the same place. That means

1) any feature values from the previous layer are lost
2) any relations that may have attached to the old layer are deleted

... so in order for the user to not accidentally lose data by changing the layer, there was a confirmation popup asking
the user if they are certain they want to change the layer.

Furthermore, it was a problem when a user tried to create a new annotation on a different layer. Lets say the user has
just created an annotation on layer A and then wanted to create another annotation on layer B. So the user would use the
dropdown to select another layer. That would then trigger the popup warning the user about changing the layer of the
currently selected annotation.

To create an annotation on a different layer, the user would first have had to use the "Clear" button to clear the current
selection and then choose the new layer using the dropdown and then create the new annotation.

Furthermore, let's say you were mainly working on layer A but for some reason, you wanted to briefly inspect or edit an
annotation on layer B in between. So you would have selected the annotation on layer B and then you would have selected
a new span to create a new annotation. Because the layer dropdown now showed "B" (because that is the layer of the annotation
you just selected), the new annotation would be on layer B, not layer A. So you'd have had to switch the layer type
and go through the popup again - or you would have to delete the annotation (also clearing the selection in the process),
then switch the layer, then create a new annotation...

... so that is the reason why you cannot change the type of layer after the annotation has been created and also why the layer
dropdown has been decoupled from the type of the currently selected annotation.

In INCEpTION, the layer dropdown works like selecting a "brush" that use to paint your annotations. It allows to easily and
quickly create many annotations on the same layer. In particular for projects that have few or even only one layer, this
is convenient.

Most information goes into feature values anyway. E.g. instead of having one layer for say "Person", "Organzation" and
"Location", having a single layer "Named Entity" with a string feature "value" and the tagset "Person", "Organzation" and
"Location" can be used - no problem with layer switching. Also, you can bind hot-keys to feature values (but currently not
to layer selection).

That said, there may be cases where people do have many different layer types and may frequently have to switch between
layers in order to do their annotations. Maybe in the future, there might be an option for "deferred" layer choice where
you first select the span and then select the layer (maybe through a popup) - but it is quite unlikely that the option
to switch the type of an existing annotation comes back.

Cheers,

-- Richard