[OSM-dev] [Tilesathome] I'd like a list of the file size of all z12 tilesets

[Ævar Arnfjörð Bjarmason]

2009/5/21 Ævar Arnfjörð Bjarmason <avarab at gmail.com>:
> On Wed, May 20, 2009 at 6:53 PM, Sebastian Spaeth <sebastian at sspaeth.de> wrote:
>> Ævar Arnfjörð Bjarmason wrote:
>>> I want to play with producing a heat map of the globe where "heat" is
>>> determined by the relative size of t at h tilesets at z12.
>>>
>>> I could also use the tiles themselves, but I suppose the tilesets will
>>> be a better indicator of complexity. But whatever's easy.
>>>
>>> Could someone with access to the t at h servers pretty please generate
>>> this for me? :)
>>
>> 20:51 < spaetz> http://tah.openstreetmap.org/media/filesizes.bz2
>> 20:52 < spaetz> result of ls --file-type -l -R > filesizes
>> 20:52 < spaetz> takes some grepping, and cutting to get the raw sizes,
>> but the
>>                info is in there.
>
> I converted it to something better using a hacky ad-hoc script (attached):
>
> http://u.nix.is/~avar/tile-sizes.txt.bz2

I went ahead and created a renderer so it now makes a heat map, it's
under applications/rendering/tah-heatmap in svn:

http://trac.openstreetmap.org/changeset/15441

Example output here:

http://u.nix.is/~avar/osm-heatmap.png

And how to run it:

http://trac.openstreetmap.org/browser/applications/rendering/tah-heatmap/README

Ideally this map would be mostly red around large capital areas and
blue along most of the coastline and other sparsely mapped areas. But
the heatmap() function I ripped from ViewCVS takes values between 0
and < 1 (which I normalize to with $tile_size/$max_tile_size) and
since most tiles fall towards the lower end of the size spectrum the
map ends up being mostly blue.

I've been trying to find an algorithm which would intelligently
distribute these values so I'd get the blue/yellow/green/red colors
which compose the canonical heat map, but such numeric crunching isn't
my strongest side. Help would be appreciated.

These are the min/max/average/median t at h tile sizes, for reference:

Min = 5472
Max = 38211510
Average = 551490
Median = 227879
Number of tiles = 937254