File:Int32 bits over lat.png

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Using a binary planet.osm, coordinates can be converted from double (64bit) to int32. Bit consumption of longtiude is constantly 31 bit for 1cm resolution, and latitudes only require 32bit around the equator. As circumference decreases with increasing latitudes, some bits can be saved - at least when using a file as storage.

This graph shows how many bits are required to achieve 1cm resolution for lat values; The actual savings depend on node distribution.

Looks like it's not very much.

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current20:26, 7 September 2006Thumbnail for version as of 20:26, 7 September 20061,060 × 742 (5 KB)Wollschaf (Talk | contribs)Using a binary planet.osm, coordinates can be converted from double (64bit) to int32. Bit consumption of lon is constantly 32bit for 1cm resolution, but latitudes only require 32bit around the equator. As circumference decreases with increasing latitudes
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