Thursday, February 5, 2009

Tour: Test Drive

I've had my first serious test drive with the tour functionality today so here are some quick notes:

Layer Change Recording: IMHO the best use of the tour is not to showcase the wonders of Google (mountains in 3D, undersea volcanoes and the like) but to add data, interpretation or annotations as the narration continues. So the ability to turn on and off layers in a tour is crucial. To see what I mean compare Frank's tour of the Grand Canyon (no criticism of Frank by the way, I'm just making a general point) with the Brahmaputra Lesson plan tour I've just created (warning 2.3Mb) :

Audio Tour of the Brahmaputra

You can see that my polygon around the Himalayas is annotation and that I've added an overlay image which is data (or maybe more annotations if you want to quibble) and that the layers turn on and off themselves. In essence, my tour is a mash up of my elements that I'm presenting against the GEarth canvas whereas Frank is talking about the canvas itself.

Stefan at Ogle Earth, reports that the tour doesn't record overlay changes. Well, I got it to do so but maybe that's because my overlays were in folders. You'll note that I instruct the viewer to turn layers on or off via the audio narration, that's because of flakiness that I found, see note below.

Audio and Movement perform well: In recording this I had little problems with the flight not recording correctly or the audio not syncing. It all worked as expected except that the tour does not seem to fly the camera view to the right starting position sometimes.

Beta Flakiness with Layer control: However, the layer control is flaky in parts, sometimes it just doesn't seem to work at all and it gets confused if you fast forward, rewind or move the play head about. So I'm not going to use the tour functionality in anger just yet but, hey, that's what beta versions are all about :)

3 comments:

JB said...

Rich,

Great point about GE being a canvas, but you don’t need the radioFolder. The key is the use of XML ids for all features and the Update tag. It’s best to structure your file as a Document which contains a Folder (with all your Overlays, Placemarks, etc) and a tour (not in the Folder).

Set the Document to open with visibility=1 but with all the KML feature contents at visibility=0. Also at the start of tour use gx:AnimatedUpdate to set the initial visibility of all features equal to 0 or 1 depending upon if you want them on or not at the start of the tour.

Then use gx:AnimatedUpdate to turn on features through the Tour when you need them, and to turn off when you no longer need them. To start the Tour double-click on the Tour icon in your file in (or highlight and press the play button at the bottom of Layers).

If the file is loaded already and the features are currently a mixture of on and off, check the top level box (should be for a Document or Folder) and turn everything on. Then start the Tour as described above, and the visibility states set in the feature KML and AnimatedUpdates will take care of everything.

Note that Placemarks, description balloons, Polygons, Polylines, Models, Overlays (but no exploring ability for PhotoOverlays), and even NetworkLinks can all accessed by the tour. But of course the need to be in a stable location accessed by the Tour (e.g. at a set URL or wrapped into a KMZ with the Tour’s KML). Also Styles can be updated during the Tour, and using the time-tag extension for default views you can sync to historical imagery (this icon must be manually activated to work during the Tour).

However, don’t take my word for it. This blog post is by the Googler who put an incredible effort into make the tour function a reality:
http://google-latlong.blogspot.com/2009/02/google-earths-flying-tour-bus.html

Also Google’s developers guide should clear up most confusions:
http://code.google.com/apis/kml/documentation/touring.html

Carharty said...

I, too, believe that the touring feature of GE5 is a watershed. The Brahmaputra example was very helpful. I noticed that after the first, the radio buttons were automatically activated. I was left in Yorkshire, however, and wanted to get back to the Himalayas sooner. I had to exit the tour in order to turn on the last video. Still, this is wonderful. How do you control flying? Placemark to Placemark? Do you have the Connexions 3D mouse? I'll be checking your site often!

Rich Treves said...

Hi Carharty,

I think the 3DConnexions mouse is a little overhyped, I usually don't use it. Instead, I would advise setting up placemarks with the correct view and double clicking on these in the places panel to navigate around during a tour. This creates a smooth flight between areas of interest.

Rich