April, I am not familiar with Operations Dashboard but if it behaves like AGOL then you could likely put in a filter for the poles, if they have an attribute of that county name.
This link may help:
Andrian made a good point that if your Poles layer has a County attribute, you can create a filter data source using this County attribute. And depending on what context you're trying to do the filtering and/or selection, you can use the Layer Filters map tool or the Query widget as well.
If you want to do spatial selection with the out-of-the-box tools, at this point you can only use the map's current extent and not features from a data source (please see to this documentation for details). However, you can easily write an extension to do more complicated spatial operation like the one you're trying to do. I have a small sample extension that I can share with you if you're interested
The poles layer I am using for this query does not have a county attribute, so the filter option doesn't work.
Yes, please do send me the sample extension. Writing extensions and widgets still intimidates me, but maybe having one to start from will help ease my anxiety!
I have uploaded the sample to this location with steps about how to use it with your operation view. Please note that there's a bug in the 3.16 JSAPI that causes selection not to work properly (all features will be selected). We have a fix for the issue already and it will be rolled out with the 3.17 JSAPI when it is released.
Feel free to leave us a comment here or post your question in the forum if you run into problem writing extensions or using the app, or if you have suggestions on what features you want to have in the future.
To add to Chris's point, our extensibility framework is currently only available in the 3.x codebase and we're working on the 4.x version, so for now if we develop a Dashboard extension, we'll have to use the 3.x API.
Thanks for the great question!