Add option to adjust distance rings around current position.

I use Locus frequently for Geocaching. It settings it is possible to display distance rings around your position. It seems that these distance rings are pre-set to specific distances and cannot be adjusted. It would be nice to have the option to adjust the radius of these distance rings to any desired amount.

For example: When geocaching, if you want to place a new cache, it must be 161m from any other cache nearby. It would be nice to adjust the distance ring to 161m to see whether other caches are outside that distance.

Thank you.