I understand how projections work -- especially in V2 where I use my
own projections for certain types of maps.

Thank you for point out the implementation of MercatorProjection.
However, the fact that someone (probably a google employee) couldn't
figure out how to get the current projection in a sane way only
reinforces my view that there is *no sane way* to get the current
projection of the underlying map when you are coding a MapType which
is added as an overlay. The documentation indicates that the
projection is given to you, but it doesn't actually work. Bugs happen.

As I am sure that you are aware, without knowledge of the actual
projection, you can't do the mapping from tile coordinates to lat
lng.

Philip

On Feb 16, 5:49 pm, Marcelo <[email protected]> wrote:
> On Feb 16, 8:45 pm, Philip <[email protected]> wrote:
>
> > The background is that I'm writing a custom map type that can be
> > overlayed on an existing map type. However, I need to convert the tile
> > coordinates into lat/lng. This needs a MapCanvasProjection object, but
> > they are hard to come by.
>
> There's a good explanation of how conversions work in V3 
> here:http://code.google.com/apis/maps/documentation/v3/overlays.html#Custo...
>
> This example contains a MercatorProjection 
> object:http://code.google.com/apis/maps/documentation/v3/examples/map-coordi...
>
> --
> Marcelo -http://maps.forum.nu
> --
>
>
>
> > The documentation on MapType is pretty limited. I need the current
> > projection (to convert tile coords back into latlng). This is listed
> > as a property of the MapType, but it certainly isn't being set (by the
> > time that the first getTile method is called). [Also, I note that the
> > type of projection property is probably wrong in the documentation
> > as well]. So I thought I would just grab the projection from the
> > current map type being displayed. However the mapTypes on the main map
> > is a MapTypeRegistry and even though the getter method is probably
> > 'get', I can't figure out the argument to get the current (or any)
> > MapType. In particular, map.mapTypes.get(map.getMapTypeId()) returns
> > null.
>
> > Philip
>
>

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