re: using sint32 for storing lat/lon
Someday I’d really like to fix this slight goof. I should have used fixed32, because the numbers are currently guaranteed to be large. This would save one byte per lat/lon. But I’ve been avoiding it because we’d either need to include a little bits of backwards compatiblity glue, or it would require all nodes to update. Because the wire format is not the same.
re: using floats
I used ints because 32 bit floats don’t have enough bits of mantissa (I forget, they have about 21 bits?).