You could use a flat map and simulate a map tile. AI2 Flat Map Tutorial . Use OpenStreetMaps (not the Map component) to create an aerial map, use that map as described in the link. Since the map is plotted as the background of a Canvas, you can draw lines and circles with the Canvas tools. This map will work offline. Spotted location from the LocationSensor will not be precise.
The MIT map component can work off line in a limited way because the app you create caches map tiles that have already been visited. Use the Circle and Polygon Map objects to "draw few lines or circles " on the map could work. This map will work offline over a limited area (the Blocks your app has already visited while connected online). Spotted location from the LocationSensor will be precise.
Similar to the first idea, however create your flat map on https://geojson.io and use the tools to draw lines and circles.
Experiment. All these techniques do work. Yes I have completed Projects using them whether they are useful or not for your application I have no Idea. Good luck.