[OpenLayers-Dev] [crschmidt@metacarta.com: [OSM-dev] Faster Commercial Layers]

Christopher Schmidt crschmidt at metacarta.com
Wed Nov 21 08:20:41 EST 2007

Sigh. Sending emails at 3:45 is worse than committing at 3:30. This went
to the osm-dev instead of ol-dev list.

-- Chris

----- Forwarded message from Christopher Schmidt <crschmidt at metacarta.com> -----

From: Christopher Schmidt <crschmidt at metacarta.com>
To: dev at openstreetmap.org
Date: Wed, 21 Nov 2007 03:49:34 -0500
Subject: [OSM-dev] Faster Commercial Layers

The three commonly used commercial layers -- Google, VirtualEarth, and
Yahoo -- now each have a mechanism using the internals of their
respective APIs to grab faster ways to move map tiles around. 

http://openlayers.org/dev/examples/spherical-mercator.html now
demonstrates this.

Erik reports that IE is throwing an error. Since is it 3:45 in the
morning, I'm going to go to sleep now, get an early start and try to
hack on the IE issue first thing before work, and get it resolved.

In the meantime, Firefox browsers might be interested in checking the
uRL above and checking out the other APIs. 

(Note that Yahoo/VE both have weird ideas about what to do when viewing
the whole world -- best to zoom in a couple notches.)

Additionally, there is an option on the EventPane layer class:

{Boolean} smoothDragPan determines whether non-public/internal API
methods are used for better performance while dragging EventPane layers.
When not in sphericalMercator mode, the smoother dragging doesn’t
actually move north/south directly with the number of pixels moved,
resulting in a slight offset when you drag your mouse north south with
this option on.  If this visual disparity bothers you, you should turn
this option off, or use spherical mercator.  Default is on.

Feedback welcome; I'm hoping that at least some if it will be positive

Christopher Schmidt

dev mailing list
dev at openstreetmap.org

----- End forwarded message -----

Christopher Schmidt

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