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You can add circle polygons to maps to users using CircleLayer().
Due to the nature of the Earth being a sphere, drawing lines perfectly requires large amounts of difficult maths that may not behave correctly when given certain edge-cases.
Avoid creating large polygons, or polygons that cross the edges of the map, as this may create undesired results.
Excessive use of circles will create performance issues and lag/'jank' as the user interacts with the map. See for more information.