[MapProxy] Resolution and Levels

[Oliver Tonnhofer]

On 20.04.2011, at 18:04, Oliver Schöne wrote: 
> 
> grids:
>   EPSG_4326:
>     srs: EPSG:4326
>     bbox: [5,35,16,56]
>     bbox_srs: EPSG:4326
>     res_factor: ‘sqrt2’
>     tile_size: [256, 256]
>  
> This automatically generates 19 levels from 0.08203125 (at level 0) to 1.56462192535e-07 (level 19). What does this mean?

There are 20 levels by default (including level 0), you can change that number with the num_levels option. 

> What ifI want to render exact scales in EPSG:4326 for example like this: (scales mean 1:10000000, 1:25000 …  in metric units)?
>  
> res: [10000000, 5000000, 4000000, 2000000, 1000000, 500000, 250000, 100000, 50000, 25000, 10000, 7500, 5000]

You need to use resolution for the `res` option. Scale is something surveyors and cartographers are used to since hundreds of years, but it doesn't make sense in the world of pixels. :)
See: http://mapproxy.org/docs/latest/configuration.html#scale-vs-resolution


Regards,
Oliver

-- 
Oliver Tonnhofer    | Omniscale GmbH & Co KG    | http://omniscale.de
http://mapproxy.org | https://bitbucket.org/olt | @oltonn