[OSM-dev] Proposal: Database accelerator and dirty tile marker based on simple algorithm.

[Nigel Magnay]

>
>
> The 180-200 is in the context of what I said, an invalid range. I think
> we are basically agreeing but disagreeing on the words used to describe.
>
> I am actually positing a range of 0-214.7483648 but only using 0-180.
> This provides easy degree conversion.
>
>
Ok - that's cool, I can live with that especially since the loss of
precision is so trivial as to be unimportant.

The disadvantage is though that you have a bit of work to do in areas which
overlap (the +/-180 line), which you wouldn't have if the grid fit the globe
exactly - this is going to be a bit of a pain for things like coastlines.

  The only thing that I think is bothering me is the "then interleave" step.
To perform this function don't you need to recurse around the 1E7 lon and
lat figures shifting bits off, and isn't that exactly the same as my inner
loop ? And if that's the case, the fact that it's a 1E7 multiplication a bit
unimportant, because that's not the "hard bit"? Or is there some fancier way
of interleaving bits I haven't thought of?
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