[OSGeo-Discuss] fastest option of serving huge imagery on web map on the fly

[Oliver Tonnhofer]

On 22.05.2010, at 21:26, Jason Birch wrote:
> I've often wondered if power-of-two was the best approach from a
> perception viewpoint. It definitely makes the most sense from a code
> perspective. Anyone know of any research on this?


No research, but we invested some time while developing MapProxy and looked for alternatives. We came up with power-of-1.41421, the square root of two. Together with some other tricks (like bicubic resampling, etc) you can get pretty good results for vector data. The benefit of sqrt(2) is that every second level exactly matches the resolution of the traditional power-of-two pyramid, which is important if you use clients like OpenLayers.

See http://osm.omniscale.net/proxy/service? wich uses the same data as http://osm.omniscale.de/

Regards,
Oliver

-- 
Oliver Tonnhofer <olt at omniscale.de>
Omniscale - Dominik Helle, Oliver Tonnhofer GbR
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