[OSM-dev] Lite OSM backend

Wollschaf mith at uni.de
Thu Sep 7 21:39:03 BST 2006


On Thu, 07 Sep 2006 00:20:01 +0100, Jon Burgess wrote:

> I reckon a good option for the lat/lon would be a 32bit fixed point
> number. I think 2^32 data points over +-180 degrees gives a resolution
> of about 1cm across the globe (40,000 km circumference / 4 billion).

A great idea. :)

I tried to find out how much space can be saved by using
variable-bitlength integers while storing the data in a file.

Not so much, I suppose:
http://wiki.openstreetmap.org/index.php/Image:Int32_bits_over_lat.png

At least not enough to justify the hassle of coding that ;)

Wollschaf





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