Animating historical imagery using Google Earth Tours

Last year we showed you how to animate Google Earth historical imagery using the Google Earth plugin. However, the Google Earth plugin has been deprecated and is set to stop working on December 12th, 2015. In addition, Google Chrome and other browsers are making it harder to use the plugin.

So, we have decided to try and achieve the same thing using Google Earth Tours. In a Google Earth Tour it is possible to specify particular views that include not just the position and angle, but also whether or not to show ‘historical imagery’ and when in ‘historical imagery’ what exact date to show. It is, however, not easy to create a Tour to animate historical imagery using just the built in functionality of Google Earth, so instead we have decided to do it via JavaScript.

To use it, the first step is to decide what view you want in Google Earth. Create a Placemark in Google Earth then save it as a KML file. Do make sure it is KML not KMZ, as our script cannot read KMZ. Next, decide on your settings below and and upload the Placemark file. Then click on the “Create Tour” link to download the generated KML tour for you to view in Google Earth.

It has been tested in Google Chrome, Firefox and Internet Explorer 11.

Start:	(yyyy-mm-dd)
End:	(yyyy-mm-dd)
Step:	YearsMonthsDays
Pause:	(seconds)
Placemark KML:

Try adjusting the settings to get the best results for a given location. Remember that the functionality works whether you want to see whole continents or zoom right in, but you will want to choose your settings depending on the availability of imagery. Although it is possible to make the pause between steps shorter than 1 second, we found that Google Earth could not keep up and simply did not refresh the screen on every step. It seemed to work alright with the 1 second setting, but if you have a slow computer or slow internet you may want to make it longer. For best results run the tour through a few times depending on the speed of your internet to cache the imagery.

We have created a few tours which you can download here to give you an idea of what is possible.

The historical imagery for Europe in the YouTube video above appears to come in waves from the top downwards. We believe this has more to do with how Google Earth refreshes the screen during the tour than the actual dates that the imagery was added.