A
Nami -
"Before navigation existed. I heard people could only sail in water where land was somehow visible. When you're sailing and you look around to see that you're surrounded by water, it makes you feel insecure, doesn't it? From then, people found a landmark that would follow you around no matter where you go. The 'North Star'. There was even an era when people actually believed the compass pointed toward the 'North Star' at one point. I'm glad I was born into this era Because I can travel anywhere to go and meet all the beautiful treasures around the world"
So Nami knows about Pole star navigation which was considered advance for other nations expect Elbaf.
And traveling from one island to another island was hard that means Log pose didn't existed 60-70 years.
Someone created Log pose during Roger's and Rocks Era.
Who that could be?

