Aside, since you’re mentioning distance, note that @jpmeijers says on the TTN Mapper website:
Which spreading factor should I transmit on?
We recommend using SF7. This provides us with a map of “worst case” coverage. Due to the 1% duty cycle limit on transmissions, using the fastest spreading factor will maximize the number of measurements taken.
From experimentation it has been seen that slower spreading factors (like SF12) does not perform well when the device is mobile. This is likely due to path fading from obstacles in the radio path, causing bursts of interference (erasures) which the forward error correction can not deal with. When you are doing measurements while standing still higher spreading factors (SF9-SF12) will work, but when mobile it’s better to use SF7.
So, the SF9 you used at the point below is not strictly forbidden, but not using SF7 might be confusing when others are using the map to evaluate gateway coverage? And I even see SF11 and SF12 for other points on your map?
