[OSM-dev] Osmosis Replication Statistics

[Robert (Jamie) Munro]

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Brett Henderson wrote:
> The only issue is that a polygon is defined by integer 
> coordinates, not doubles.  I guess I could fudge it by multiplying 
> lat/lon by a fixed constant and losing some precision but it's not ideal ...

IMHO it /is/ ideal. Using floats for lat/lon is stupid - it just
means that you are more accurate at measuring places nearer the equator
and nearer the Greenwich meridian, and less accurate as you move further
away. Use 2^N/360 as your fixed constant, where N is the number of bits
you use in your integer. 32 bits gives a precision down to less than a
cm. If you are working in a sufficiently low level language, you can
ignore overflows and signed/unsigned issues because they cancel each
other out, and crossing the date line works by magic.

Robert (Jamie) Munro
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