[OSM-dev] Blue sea for tiles at home

Frederik Ramm frederik at remote.org
Wed Apr 25 23:03:48 BST 2007


    talking about the ocean tile index used by close-areas.pl (and now 
also lowzoom.pl) to determine which tiles are "basically blue", Robert 
Hart wrote:

> Can you not document how the process is done and then we can split the 
> task over many people. I assume you are not hand editing a 4MB binary 
> file, so there must be some "source" and tools involved.
> I'd really like to see those made publically available.

Martijn has had a quite clever idea to make it easy for people to edit 
the file. He has provided a 4096x4096 PNG file in which each pixel 
corresponds to one level-12 tile, and a script that generates the 4MB 
data file from it.

I have checked everything in under tilesAtHome/tools/png2tileinfo (and a 
new data file with some fixes that Martijn has provided).

Armed with that and the Gimp or something similar, everybody should be 
able to fix the tile index if required, plus you get a quick visual 
feedback in the editor.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'

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