Caching Google Earth imagery with path tours

We have recently been catching up on the outlines for our KML of Google Earth 3D areas. The internet speeds here in Cape Town increase every year, but we still seem to spend a lot of time waiting for Google Earth imagery to load. When tracing out 3D areas, we have found it helpful to pre-cache an area before starting to draw and we thought we should share the technique, as our readers could find it useful in a variety of circumstances.

The border of the 3D imagery areas is often quite intricate.

The basic technique is very simple. Just draw a path where you wish to pre-cache imagery, then select the path and click the ‘Play Tour’ button that appears. Once the tour starts, go away and do something else for a while then come back when it is finished and you will find that imagery in the area you are interested in now loads much faster.

A ‘Play Tour’ button appears in the divider between Places and Layers whenever you select a path.

The default settings have the Google Earth ‘Camera’ follow the line quite closely and thus only imagery very near the line is cached. In addition, depending on the speed of your internet connection, the camera may move a bit too fast to fully cache the imagery before moving on. However, this can be adjusted with the settings found in Tools->Options->Touring:

We like to set the Camera Tilt Angle to zero (looking straight down) and the Camera Range to 1000 metres. Start the tour and see if the imagery is managing to load completely before it goes off screen. If not, reduce the Speed setting.

The above technique can also be used if you plan to use Google Earth offline, as you can pre-cache an area by drawing a zigzag path across it. Be sure to test it before setting off on a long journey.

To learn more about Google Earth’s cache see some of our previous posts on the topic.