[OSM-dev] tiles at home disk usage

Lars Aronsson lars at aronsson.se
Thu May 3 02:02:15 BST 2007


Robert Hart wrote:
> 
> erm. so the 2 bits per tile at level-12 file, "oceantiles_12.dat" that
> takes 4,194,304 bytes is more optimal than the 159,179 byte
> "oceantiles_12.png" file that contains the same information?
> 
> Surely we could at very least run-length encode the data?

That's exactly what the PNG format does, and does very well.  
Just use libpng as the API to read and modify individual pixels, 
and all will be fine.  Abandon that huge .dat file.


-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se




More information about the dev mailing list