There is an image classification problem about land cover/land use~~
How to get only the image in the sampling area (inside the circle)?
I think you need to remove the GeoRange value. Note that GeoRange->d means radius d.
GeoGraphics[GeoCircle[sampleCenter, Quantity[5, "Kilometers"]],
GeoRangePadding -> None, GeoBackground -> "StreetMapNoLabels"]
Or do you want only the interior of the circle?
GeoDisk[sampleCenter, Quantity[5, "Kilometers"]]},
GeoBackground -> None]