# what is the relevance of cosine in determining map resolution? [closed]

"At any latitude and zoom level, you can determine the scale by using the following equation"

``````Map resolution = 156543.04 meters/pixel * cos(latitude) / (2 ^ zoomlevel)
``````

is a quote from (http://msdn.microsoft.com/en-us/library/aa940990.aspx)

Can anyone explain to me the relevance of the cos(latitude) part? I am having difficulties visualising this.

## closed as off-topic by BradHards, Fezter♦, PolyGeo♦, Paul, Jason ScheirerMar 24 '14 at 5:54

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• "Questions describing a problem that can't be reproduced and seemingly went away on its own (or went away when a typo was fixed) are off-topic as they are unlikely to help future readers." – BradHards, Fezter, PolyGeo, Paul, Jason Scheirer
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• - ok so it´s simply the ratio used to calculate the length of the distance from 0° Longitude to the tangent of the sphere, thus giving the resolution at the given latitude. – Robert Buckley Mar 22 '14 at 7:40