[MapProxy] Limit a cache to a polygon

[gdis at arcor.de]

Hi Oliver,

thanks for your reply.
I have more than 4 zoom levels but for testing purposes i only tried these 4 levels.

Here is the output of the mapproxy-util grids command:
my_grid:
    Configuration:
        bbox: [2491577.228, 5628558.771, 2593816.085, 5793394.241]
        bbox_srs: 'EPSG:31466'
        origin*: 'sw'
        res: [1222.9924523925781, 611.4962261962891, 305.74811309814453, 152.87405654907226, 76.43702827453613, 38.218514137268066
, 19.109257068634033, 9.554628534317017, 4.777314267158508, 2.388657133579254, 1.194328566789627, 0.5971642833948135, 0.2985821416
9740677, 0.14929107084870338, 0.0746455354244]
        srs: 'EPSG:31466'
        tile_size: [256, 256]
    Coverage: my_polygon covers approx. 29.4320% of the grid BBOX
    Levels: Resolutions, # x * y = total tiles (approx. tiles within coverage)
        00:  1222.9924523925781,  #      1 * 1      =        1 (0)
        01:  611.4962261962891,   #      1 * 2      =        2 (0)
        02:  305.74811309814453,  #      2 * 3      =        6 (1)
        03:  152.87405654907226,  #      3 * 5      =       15 (4)
        04:  76.43702827453613,   #      6 * 9      =       54 (15)
        05:  38.218514137268066,  #     11 * 17     =      187 (55)
        06:  19.109257068634033,  #     21 * 34     =      714 (210)
        07:  9.554628534317017,   #     42 * 68     =   2.856K (840)
        08:  4.777314267158508,   #     84 * 135    =  11.340K (3.338K)
        09:  2.388657133579254,   #    168 * 270    =  45.360K (13.350K)
        10:  1.194328566789627,   #    335 * 540    = 180.900K (53.243K)
        11:  0.5971642833948135,  #    669 * 1079   = 721.851K (212.455K)
        12:  0.29858214169740677, #   1338 * 2157   =   2.886M (849.428K)
        13:  0.14929107084870338, #   2676 * 4313   =  11.542M (3.397M)
        14:  0.0746455354244,     #   5351 * 8626   =  46.158M (13.585M)

Of course zoom level 0 contains the whole data and not only the data within the polygon because the level consists of only one tile. But when seeding zoom level 13 I would expect that only tiles touching the polygon are being created. But it seems that mapproxy is always requesting tiles for the whole bounds (there are tons of empty tiles although the polygon is completely inside the bounding box).

Regards
Hendrik