Annotation control page

[beijbom]

Right now we ask users to specify the annotation area right from the start. I think it would be nicer to delay this if possible for two reasons

1. We can then use the already-existing tool for graphically selecting the area and overlay a "ghost" image of already uploaded images. I experimented with that way back when and it actually looks really nice if you simply create an average image across 10 or so images.
2. Make it lighter to setup the source.

One idea is to basically "grab" people first time they go to the annotation tool, and direct them to a "annotation control page" (which would be under admin permission). This page would enable control of the annotation area but also to change the random point generation scheme (and perhaps also put the confidence threshold here, although it does not quite fit in?) For both of these, we should give the user control as to whether they want the new settings to apply to new images. And if they propagate the changes, we should be considerate of: https://github.com/beijbom/coralnet/issues/14 i.e. to keep as much as possible of previous work. We need to look at this for each point sampling design though, as we can not compromise the randomness in general.

[StephenChan]

One kind-of related idea: Annotation area could possibly be more intuitive if it's specified as left, right, top, and bottom margins instead of max/min x/y. The idea is to leverage users' familiarity with Word/Docs, printing documents, etc.

[beijbom]

... and we should generate a warning if the area is too small (say less than 1/4 of the image area).