[OpenLayers-Users] Maximum extent shrinks when zooming in

Christopher Schmidt crschmidt at metacarta.com
Tue Apr 15 18:09:36 EDT 2008


On Tue, Apr 15, 2008 at 03:00:28PM -0700, zenzero-2001 wrote:
> 
> Hi Christopher,
> 
> That's interesting that's it's not considered a bug. Personally, I would
> definitely think of it as a bug or possibly an undocumented feature :) I
> hope you don't think that I was complaining, I think that OpenLayers is
> great. 

Well, if you think there's a bug, you need to do further description of
the issue to convince me, is all. What you have described so far sounds
to me to be not a bug. What you have described so far sounds to me like:

 * I have a map, from (for example) -10, -3, 10, 3
 * I set a maxResolution of 6 / 256, so that my whole world fits
   vertically within one 256 px tile
 * Because my map is 20 units wide, it is 4 tiles wide, and therefore
   covers more than -10 -> 10 in the longitude direction: 24 degrees.  
 * When I zoom in, my resolution drops to 6/512:
   * Vertically, the world is two tiles. 
   * Horizontally, it is 7 tiles -- taking up less horizontal
     geographic space than before: 21 degrees.

Since you've said you can change your maxResolution, and it 'solves' the
problem, I assume that you've found that if you pick a maxResolution
that divides *evenly* into the width *and* height (in this case,
something like '2' would do: 3 tiles high, 10 tiles wide), you will see
that the tiles match your geographic space correctly.

If this is *not* what you're describing, then you'll need to be more
clear, because this behavior isn't a bug: in fact, I don't know of any
way around it.

Regards,
-- 
Christopher Schmidt
MetaCarta



More information about the Users mailing list