Tuesday, August 4, 2009

Creating Tours HowTo 2: Turning elements on and off

Screen Shot of the Goldman Prize tour

This is the second HowTo about tours of a 3 part set. It builds on Creating Tours HowTo 1, In this HowTo we learn how to turn elements on and off in a tour.

Adding Elements:
A more advanced tour than we previously discussed uses elements (e.g. placemarks, ground overlays, polygons) in the places column which are turned on and off to illustrate the topic of the tour. The Goldman prize example (screen shot above) plays in the Google Earth plugin, if you haven't got it there's a link to get the google earth file instead. It uses placemarks but you can use more sophisticated elements as in this Lake Chad Example which uses screen and ground overlays for text and to show the shrinking lake respectively.

To construct a tour turning elements on and off:
  1. Create a new empty folder (right click temporary places in your places column > Add > Folder). Name it something sensible.
  2. Copy the elements you want to appear in it from elsewhere in the places column (right click the element, then select copy, select your new folder, select paste) or create new elements within the folder.
  3. Untick any original elements you have just duplicated in their original location in the places column and all the elements in your new folder.
  4. Record the tour turning elements on and off but only from your new folder.
  5. When you have finished the tour click the stop button in the tour dialogue. The tour will play itself automatically but the elements will not appear as there's a bug. The workaround is to save the tour (floppy disk icon in the record dialogue bottom left of your screen), name it something sensible and then play it again - it should now work.
  6. Drag the tour element that you've just created in the places column into the new folder if it isn't there already.
  7. Make sure all the elements are turned off and save the new folder as a .kmz file (right click>Save As). Google Earth records the visibility of your placemarks when saving a .kmz so the tour will automatically open with the elements unselected, by doing this you avoid the problem mentioned in [4].
Why Use a Folder? Google Earth records your tour as a series of instructions, it will look for 'Placemark X' to turn on and off in your places column if this is included in your tour. By saving all the elements in a folder in this way we ensure they appear in the places column of your users so the tour will play properly.

The camera viewpoints discussed in the previous post can be used as before, but note that it is not necessary to save any camera viewpoint placemarks in the new folder, their location is stored in the tour part recording automatically of the KMZ. Removing them from the folder is good practices as it unclutters the view in the Places column.

Adding Text Notes: You can add placemark text notes to your tour by adding placemarks and opening them in a tour. For example, if I was producing a tour of the Southampton University campus I could mark the School of Geography building with a Placemark called 'Geography'. In the description I could add detail such as 'We run a successful program of Undergraduate, Masters level and continuing professional development courses'. In the tour I would fly to view the building, make the placemark appear by ticking its box in the places column. When the users had had time to register what the placemark's name is (a couple of seconds) I would then click it in the main screen to make the description appear.


Keith said...

Great Information! Thank you so much for creating these HowTos.

Any chance you'd be able to share how one can record a tour AND keep the colored path in view during the playback of a recorded tour?

Example: I've recorded a tour or a hiking route and have the route path shown on my GE. When I save the file (.kml .kmz) to my webhost and call it into my website, the tour plays but not colored path. How to keep the path in recorded tour playback?



Rich Treves said...

Hi Keith,

The answer is to wrap up the tour in a folder with the path selected (so its visible) and save the folder as a .kmz rather than just the tour.


Keith said...

Much Thanks Rich,

Your advice worked a charm, so I'm back with another GE problem.


I'm creating a custom tour, and I'm using Placemarks along my path/trail. Tour starts and camera nicely zooms into first and second placemarks along the trail. BUT the third placemark involves and 180 degree turn so the hiker/camera can see what the view looks like behind them. Instead of just a nice 180 rotation the camera swoops way out and then swoops back in (giving views nausea) and only 50% of the time will it land in the correct viewing position. Sometimes I have to click on the placemark 2xs just to get it to the correct position.

Why does the flying camera not seem to take the route of least resistance?

I know I could just do this manually by hand/mouse/keyboard, but that too is too jerky and would prefer to use the placemark tour without the swooping.

I've set up a video capture of the challenge. Please see...
title: Google Earth Extreme Zooming


Any help or insight you can give would be great!



Rich Treves said...


Yeah, the route GE takes between views can be annoying. Try adding additional views between the two points. Can't predict how this will turn out but I suspect if you straighten up to a vertical view then rotate, then move to next view it will be more sensible.

Keep us posted on progress!