[MapProxy] min_res in default grids
Denis Rykov
rykovd at gmail.com
Thu Mar 24 08:11:30 PDT 2016
My use case: I need to calculate number of tiles for particular city in
GLOBAL_WEBMERCATOR grid which I will display over OSM basemap. Grid config
grids:
moscow:
base: GLOBAL_WEBMERCATOR
bbox: "37.3352,55.5496,37.893,55.9184"
bbox_srs: EPSG:4326
num_levels: 19
Result:
$ mapproxy-util grids --grid moscow --mapproxy-conf mapproxy.yaml
moscow:
Configuration:
base: 'GLOBAL_WEBMERCATOR'
bbox: '37.3352,55.5496,37.893,55.9184'
bbox_srs: 'EPSG:4326'
num_levels: 19
origin*: 'ul'
tile_size*: [256, 256]
Levels: Resolutions, # x * y = total tiles
00: 284.8329187718773, # 1 * 1 = 1
01: 142.41645938593865, # 2 * 2 = 4
02: 71.20822969296933, # 4 * 4 = 16
03: 35.60411484648466, # 7 * 8 = 56
04: 17.80205742324233, # 14 * 16 = 224
05: 8.901028711621166, # 28 * 32 = 896
06: 4.450514355810583, # 55 * 64 = 3.520K
07: 2.2252571779052914, # 109 * 128 = 13.952K
08: 1.1126285889526457, # 218 * 256 = 55.808K
09: 0.5563142944763229, # 436 * 512 = 223.232K
10: 0.27815714723816143, # 873 * 1024 = 893.952K
11: 0.13907857361908071, # 1745 * 2048 = 3.574M
12: 0.06953928680954036, # 3489 * 4096 = 14.291M
13: 0.03476964340477018, # 6977 * 8192 = 57.156M
14: 0.01738482170238509, # 13953 * 16384 = 228.606M
15: 0.008692410851192545, # 27905 * 32768 = 914.391M
16: 0.004346205425596272, # 55809 * 65536 = 3.657G
17: 0.002173102712798136, # 111617 * 131072 = 14.630G
18: 0.001086551356399068, # 223234 * 262144 = 58.519G
As you can see in this case min_res is calculated from bbox. But I have
expected that min_res will be 156543.03, becaue I use 'GLOBAL_WEBMERCATOR'
as base.
For correct calculation I have to manuall specify min_res:
moscow:
base: GLOBAL_WEBMERCATOR
min_res: 156543.03
bbox: "37.3352,55.5496,37.893,55.9184"
bbox_srs: EPSG:4326
num_levels: 19
$ mapproxy-util grids --grid moscow --mapproxy-conf mapproxy.yaml
moscow:
Configuration:
base: 'GLOBAL_WEBMERCATOR'
bbox: '37.3352,55.5496,37.893,55.9184'
bbox_srs: 'EPSG:4326'
min_res: 156543.03
num_levels: 19
origin*: 'ul'
tile_size*: [256, 256]
Levels: Resolutions, # x * y = total tiles
00: 156543.03, # 1 * 1 = 1
01: 78271.515, # 1 * 1 = 1
02: 39135.7575, # 1 * 1 = 1
03: 19567.87875, # 1 * 1 = 1
04: 9783.939375, # 1 * 1 = 1
05: 4891.9696875, # 1 * 1 = 1
06: 2445.98484375, # 1 * 1 = 1
07: 1222.992421875, # 1 * 1 = 1
08: 611.4962109375, # 1 * 1 = 1
09: 305.74810546875, # 1 * 1 = 1
10: 152.874052734375, # 2 * 2 = 4
11: 76.4370263671875, # 4 * 4 = 16
12: 38.21851318359375, # 7 * 8 = 56
13: 19.109256591796875, # 13 * 15 = 195
14: 9.554628295898437, # 26 * 30 = 780
15: 4.777314147949219, # 51 * 60 = 3.060K
16: 2.3886570739746094, # 102 * 120 = 12.240K
17: 1.1943285369873047, # 204 * 239 = 48.756K
18: 0.5971642684936523, # 407 * 477 = 194.139K
On Thu, Mar 24, 2016 at 8:49 PM, Oliver Tonnhofer <olt at omniscale.de> wrote:
> Hi,
>
> > On 24.03.2016, at 15:26, Denis Rykov <rykovd at gmail.com> wrote:
> >
> > It make sense. But if grid has GLOBAL_* name it is expected that for
> calculation of min_res - global (-180,-90,180,90) bbox will be used.
> Otherwise why is it global.
>
> I don't understand your question. MapProxy defines default bounding boxes
> for EPSG:4328 and EPSG:3857. That's how it calculates the min_res. Maybe
> this makes it more clear? See
> https://github.com/mapproxy/mapproxy/blob/master/mapproxy/grid.py#L67
>
>
> Regards,
> Oliver
>
> --
> Oliver Tonnhofer | Omniscale GmbH & Co KG | http://omniscale.com
> OpenStreetMap WMS and tile services | http://maps.omniscale.com
>
>
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