when :valid
'-0.3565352711206896,51.464740877658045,-0.2686446461206896,51.508686190158045'
when :min_lat_more_than_max_lat
- '-0.3565352711206896,-0.2686446461206896,51.508686190158045,51.464740877658045'
+ '-0.3565352711206896,51.508686190158045,-0.2686446461206896,51.464740877658045'
when :min_lon_more_than_max_lon
'51.464740877658045,-0.2686446461206896,51.508686190158045,-0.3565352711206896'
end