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I try to pan Google Earth relative to the current view with the GE-PlugIn in C# (Interop.GEPlugin.dll) as described in the documentation (https://developers.google.com/earth/documentation/camera_control) with a fixed FlyToSpeed.

While setting the FlyToSpeed to SPEED_TELEPORT, everything works fine as expected:

ge.getOptions().setFlyToSpeed(ge.SPEED_TELEPORT);
var lookAt = ge.getView().copyAsLookAt(ge.ALTITUDE_ABSOLUTE)
lookAt.setLongitude(lookAt.getLongitude() + 1);
ge.getView().setAbstractView(lookAt); // Works as expected

Setting the FlyToSpeed to specific number, the panning is disturbed with a increasing zoom out behavior:

ge.getOptions().setFlyToSpeed(3);
var lookAt = ge.getView().copyAsLookAt(ge.ALTITUDE_ABSOLUTE)
lookAt.setLongitude(lookAt.getLongitude() + 1);
ge.getView().setAbstractView(lookAt); // why the view zooms out while panning?

If anybody had an idea or an approach, I would be very happy. Thank you in advance for your help.

user3704293
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1 Answers1

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why does the view zoom out while panning?

This isn't an error, it is the default behaviour.

If the fly to speed is set to something other than SPEED_TELEPORT the plugin will zoom out towards the midpoint of the movement then zoom back in towards the end in a looping motion.

AFAIK there is no way to control this other than the speed it happens.

If you wanted to implement a "fly to at fixed altitude/range" you could do so pretty easily. A common way is to leave the speed at SPEED_TELEPORT (to remove the animated looping) then to move the camera manually in incremental steps via the frameEnd event.

Take a look at this example of smoothly animating a camera via 'frameEnd' - I am sure you could easily adapt it to suit your needs (top down, fixed altitude, etc).

Fraser
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  • I found a solution for my problem as you proposed by implementing the frameend-listener in Javascript. Thank you! Just one additional question: Is it possible to register the Google Earth frameend-EventListener in C# directly, instead of invoking JavaScript from C# for this application. – user3704293 Jun 17 '14 at 17:42
  • Yes it is possible, but as the events are registered via the google.earth namespace, not via the Google Earth API, so you would need to use the DLR or reflection to invoke the methods via the browser hosting the control. – Fraser Jun 26 '14 at 03:43