[OpenLayers-Dev] preserving scale on base layer switching
ahocevar at opengeo.org
Wed Feb 3 00:58:16 EST 2010
Tim Schaub wrote:
> Currently, when a new base layer is set, we determine the new resolution
> based on the previous map extent. An alternative would be to determine
> the new resolution based on the previous scale. Preserving center and
> scale makes better sense to me. I'm curious what others think.
I totally agree. This should also improve behavior when switching
between base layers with different projections/units.
> The resolution based on extent method breaks down when extents are not
> well defined. E.g. with an extent that wraps the date line. To see
> this break-down in action, follow these steps:
> 1) open http://openlayers.org/dev/examples/google.html
> 2) click to zoom all the way out (you'll see multiple worlds)
> 3) open the switcher and change base layers
> You should see the scale change.
> Apply the patch for http://trac.openlayers.org/ticket/2457 and you
> should see better behavior.
> Thanks for any feedback.
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