[OSM-talk] [OSM-dev] Y-Boundary of Mercator-Projection

Iván Sánchez Ortega ivan at sanchezortega.es
Wed Feb 4 12:38:02 GMT 2009


On Wed, February 4, 2009 13:27, Matthias Brandt wrote:
>>> i've searched the archive of this mailinglist and the wiki about the
>>> magical y-boundary set to 85.05113° (respective 180° projected) in
>>> the Mercator Projection.
>>
>> Did you have an alternative value in mind?
>
> Not really. But I would like to know, if there is any reason for this.
> I'm writing my Bachelor thesis about OpenStreetMaps and I would like to
> explain this bound.

Quadtiles, quadtiles, quadtiles. Having a big square allows you to
subdivide images in a fashion similar to quadtrees. Using rectangles would
mess things up.

-- 
Iván Sánchez Ortega <ivan at sanchezortega.es>

Un ordenador no es un televisor ni un microondas, es una herramienta
compleja.




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