Thursday, May 20, 2010

Google Earth Tours in Geog. Teaching II

part I here. This is the second of three posts, this week I finish off the 'rules of virtual flight' section. Next post will cover audio, annotations, testing and use of layers.

c] Avoid complex camera movement: It is possible to fly out from a location while changing camera tilt, bearing and camera lattitude and longitude all at the same time. This can overload the viewers ability to follow where they are and which direction they are looking, the video above illustrates this: the first section shows a complex flight broken down into 3 separate sections where the camera first moves to point vertically downwards, then gains altitude, then changes position. The return flight changes view angle, position and altitude at the same time and confuses the user as to where they have been taken.

Some views are better with a tilted camera angle such as the one of mountain in the clip. If you haven't got a good reason to tilt the camera, a vertically down view is best.

d] North is Top: Country shapes are most recognizable to users with a 'North at top' orientation. If possible your camera angle should keep this bearing in flights.

e] Keep visual cues in view: It is easier for your users to follow where they are in a GET if you keep visual cues in view (e.g. coastlines, mountain ranges etc). If there are not useful visual cues in view, you can create some placemarks that will serve the same purpose, e.g. marking major cities on the tour route.

f] Smoothness: Flights should be smooth and jerkiness is to be avoided, commonly jerkiness is related to the power of the computer (principally the graphics card) and the Fly-to speed selected.

Practicalities: The considerations here concern setting the speed of flight and smoothness of flight. If you are creating placemarks to produce your tour (see tutorial 1 ) you can adjust the speed of virtual flight by Tools > Options > Navigation > Fly-to speed.

If you access Tools > Options > Touring > When recording a tour, you get a slider. Moving this slider to the right increases the smoothness of flight (by increasing the number of 'points' in space GEarth records) but will increase the size of file users will need to open to see your tour. For small tours, the size issue isn't usually an issue. Experiment with different settings to see the effect.

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