Where to get coordinates for building Polygon in Mapbox, Google maps etc?

Question

Google Maps

Good afternoon. It is necessary to outline several polygons on the map (Mapbox). There is an example in the documentation .
Among other things, there is a three-dimensional array with the coordinates of the area to be selected.
Where do you get these coordinates from? I suspect that it is possible to pull it out somehow from the same Google maps, but, apparently, I don’t really understand the principle of operation. At least - the code from the documentation works, but it's worth trying to set some of your own coordinates - and the polygon disappears.

I tried to pick Bboxfinder , there is a tool for visually delineating the polygon, but it does not give out the heap of coordinates as in the example.

Answer 1

Click your polygon in geojson.io and paste it there.