[Tilesathome] Blank tiles...

[Łukasz Jernaś]

On Sat, Oct 11, 2008 at 8:31 PM, spaetz <osm at sspaeth.de> wrote:
> On Sat, Oct 11, 2008 at 03:33:53PM +0200, ??ukasz Jerna?? wrote:
>> Maybe an idea would be to modify the index in the v2 tileset files, to
>> keep an info if a tile was ever rendered? Additional metadata would be
>> a bit overkill...
>
> Doesn't work. If it's blank there won't be a tileset file stored.

So the format has unused fields? Quoting
http://wiki.openstreetmap.org/index.php/Tiles%40home/Tileset_as_one_file_v2:
"Each index denotes an unsigned 32-bit integer and either contains the
blankness information of the tile in question (0=unknown, 1=sea,
2=land, 3=transparent), or the offset to the spot in the file where
the PNG data of that tile starts."

Does it mean that only the offset is stored in the tileset file or the
integer value for empty tiles is somehow magically computed?

-- 
Łukasz