implement region selection per stream

[iluise]

Describe the task. It can be a feature, documentation, etc.

Now the region selection is applied equally to all streams. This is suboptimal in case of e.g. era5+cerra trainings where the scores (and the plots) should be computed only globally for ERA5 and only on Europe for CERRA.

proposal: implement a "per stream" selection of the regions. if no region is selected the scores/plots will be computed on "global" only.

Hedgedoc URL, if you are keeping notes, plots, logs in hedgedoc.

No response

Area

• datasets, data readers, data preparation and transfer
• model
• science
• infrastructure and engineering
• evaluation, export and visualization
• documentation
• performance