[OpenLayers-Users] WMS overlay alignment on Google Map baselayer

[Christopher Schmidt]

On Mon, Aug 21, 2006 at 09:03:03PM -0500, Ross Mongin wrote:
> 
> So it seems like there is some agreement that there should be  
> functionality within OpenLayers to enable WMS layers to work with  
> projected base layers.  A couple approaches seem apparent:  1) Create  
> a WMS layer subclass that would expose the key basemap methods needed  
> to calculate the correct tile bounds.  2) Handle the reprojection  
> within OpenLayers, creating the necessary class to calculate the tile  
> bounds.  I have not looked at the feasibility of doing option 1, but  
> it seems like it would make sense to allow the baselayers to handle  
> implementation of calculating the correct conversions from pixel x, y  
> to lat / lon.  Option 2 seems like it would be tough to manage as  
> more baselayers become availible, each with thier own projection  
> nuances.
> 
> Thoughts / suggestions?

Ross -- 

There's a ticket open in Trac,
http://trac.openlayers.org/ticket/196#preview , with a description of
the way this feature will probably need to be implemented: specifically,
using map.getLatLonFrom*Px. (* is because there are three methods
similar to this, and I don't know exactly which one is needed.) 

If there's a good patch for this functionality on the ticket, it might
be possible to get it into 2.1 instead of 2.2. I hope the description in 
the ticket is adequate to get started -- the place to start reading the
code is Layer/Grid.js, and you'll want to look for anyplace that calls
tile.moveTo or layer.addTile.

Regards,
Christopher Schmidt