Hi,
for various how-many-tiles-are-there calculations I used to compute
the total number of tiles and then say "70% is water".
Just now I was curious to find out how much water there is in our
spherical Mercator projection. Turns out that the "root tile" at z0 has...
r g b lum count
----- ----- ----- ----- -------
181 209 206 200 39482
233 234 227 233 26054
... exactly 39482 / 65536 = 60% of water. But if I remove Antarctica
(i.e. count it as water too) then the figure is almost 80%. So it is
probably a realistic assumption that only 20% of Earth's surface have to
be considered "interesting" for the purpose of creating surface tiles.
Bye
Frederik
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