When in the GO 4 app map view there is a blue dot that I understand represents the location of my mobile device.  Then there is a larger blue circle around the blue dot.

What does the larger blue circle represent?

The max flight radius, your Spark can fly around you, with the settings you have.
Mobile device only, should be 100m

The blue dot shows you where you are on the map. When DJI GO 4 isn’t sure about the location of your mobile phone, you’ll see a blue circle around the blue dot. You might be anywhere within the light blue circle. The smaller the circle, the more certain the app is about the location of your phone

outsch, I confused that with the green circle, that I have every now and then, when I set a max flight distance.
Sorry!