[Chameleon] zoomscale

[Paul Spencer]

John,

I think this is a valid request and your assessment of the problem 
appears to be corrrect, but pls note that the widget doesn't claim to 
center the map on the point :)

Your solution is a quick fix, but having reviewed the code it seems to 
me that there is quite a lot of extra code in there for such a simple 
request.  This is because we are trying to reuse existing navigation 
code and it all works on user input from pixel locations.  I will file a 
bug to review this and look at providing some simpler code that 
navigates based on geographic location.

Cheers,

Paul

John Pulles wrote:

> Hi list,
> 
> It seems a (modified) Locate widget does not do an accurate zoom to 
> scale. We modified the Locate widget to zoom to a scale of 50000 and 
> noticed that the centre of the map was not close to the requested 
> location. Looking into the code (at the end of the parseUrl function of 
> the Locate widget) the problem seems that first the pixel coordinates 
> are calculated based on the full (?) extent of the map; after this the 
> zoom function is called.
> I am not sure if I fully comprehend the code, but it seems more logical 
> to me if the zoom function would use map/world coordinates instead of 
> pixels, or else calculate the pixel coordinates after the zoom-to-scale 
> has been done.
> The workaround seems to be to use the MapNavigator->recentre function 
> after having recalculated the pixel coordinates with the extent 
> after-the-zoomin. Is this the correct way, or should something else be 
> done?
> 
> Regards,
> John.
> 

-- 
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|Paul Spencer                           spencer@dmsolutions.ca    |
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|Applications & Software Development                              |
|DM Solutions Group Inc                 http://www.dmsolutions.ca/|
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