[ka-Map-users] Scale to viewport

Stephen Woodbridge woodbri at swoodbridge.com
Tue Jan 24 11:49:14 EST 2006


David Badke wrote:
> Thanks for your responses - I get it now! I will add the necessary scale 
> factors.
> 
> I still have a related question: why are the scale factors fixed as they 
> are (that is, in the map array)? Is this a design choice, a requirement, 
> or what? Not that I am saying it is bad, I just don't understand the why 
> of it...

This comes from the concept of serving pre-rendered tiles like google 
which in essence is what ka-map is doing. Yes it is generating the tiles 
on the fly, but all the advantage is the after a while all the tiles you 
need are pre-generated and cached so it is fast.

The more zoom scales you have the more sets of tiles you have to 
generate. Hence the fixed (planned) number of zoom scales to you can 
plan the disk space you need.

-Steve


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