Question: Why are the annotation tools not enabled for all resolution levels?

[kabilar]

Hi Webknossos team,

We have noticed that the annotation tools (e.g. brush, trace) are disabled at higher resolution levels and found the accompanying source code. Curious as to if there are technical limitations for enabling this for all resolution levels. If not, we will enable it on our Webknossos deployment. Thank you.

cc @jingjingwu1225 @aaronkanzer

[fm3]

I think this is to prevent users from accidentally creating massive amounts of data. If your finest mag is 1-1-1, but you zoom out to 1024-1024-1024 and then brush around some, it will create many thousands of data chunks upsampled in mag 1-1-1.

If users need to brush on coarse mags, they are usually not really interested in the fine-resolution data. We therefore suggest to create an annotation that starts only at e.g. mag 64 (click the three dots next to “create Annotation” in the dataset dashboard). mag64 will then be the finest mag in the annotation, so brushing will be enabled there, as no upsampling to mag1 needs to happen. But on the other hand, you can no longer zoom in to the original mag and brush there in fine detail.

Maybe this solves your use case as well. Otherwise, if you need both coarse and fine at the same time, you can also remove this limitating code for your fork, but beware that the volume annotations may become rather huge for the finer mags, leading to e.g. slow zip downloads with potentially hundreds of thousands of little chunk files in them.