don't understand scale

[Douglass Davis]

Ok, so the scale is relative to the units used in the mapfile.  I still 
don't quite understand.  This example would help me a lot if any one 
could explain it.

let's say I have a map with (fictitional units)

EXTENT 100 100 200 300

Now...  For example, what scale number will I have to use in zoomScale 
to get a map scaled to exactly 100%.  Meaning, exactly the same map I 
would get without scaling.  From that number I can get the other scales.

And can any one explain how they got this mathematically?

---
http://www.douglassdavis.com


Douglass Davis wrote:

> I am using php mapscript, and i want to zoom in to a point.  I have 
> two options:
>
> zoomPoint and zoomScale...  I understand zoomPoint, because it just 
> zooms by a percentage.  But, zoomScale, I am not understanding.  It 
> zooms to a certain scale, which is a double.  What does that scale 
> represent? What is the scale relative to?  The docs don't really 
> explain this well.
>
> The reason I wanted to do this, is because instead of  zooming in and 
> out relative to the previous map's extent, it would be better if I had 
> about 9 zoom levels, kind of like mapquest.  level 1 would show the 
> states, level 9 would be a close up of the street.   But each of the 9 
> levels would be a fixed zoom amount, relative to the size of the 
> original extent in the mapfile possibly.   Is this difficult to do?
>
> -- 
> http://www.douglassdavis.com
>