by Mark MacAllister
FieldTripEarth works with researchers at Thailand's TurtleWatch to monitor the locations of three satellite-tagged sea turtles released on 15 February 2010. You can use Google Earth to monitor their movements and better understand the migration patterns of each turtle.
To begin, you'll need a fairly modern computer with dependable high-speed Internet access. Download and install Google Earth and open that application on your computer.
NOTE: There are other Google Earth projects on FieldTripEarth. For example, see Elephant Tracking with Google Earth.
Instructions for Viewing Sea Turtle Tracking Maps
As you know, capturing sea turtle location data with satellite tags allows us to monitor a turtle's movements over a period of days, weeks or even months. We are interested in knowing where each turtle goes, how quickly it moves from place to place, how much distance it might cover in a particular period of time, and where/when it stays put for a period of time. We can visualize these movements using an animated "track." You can see these tracks as well using Google Earth data. Here's how:
- download the Thailand Sea Turtle Google Earth Datasets file from the Media Gallery in the right-hand margin and expand/unzip it. You should find files for three turtles: hertta, hilja and urho. These are the movement files for each of the three turtles released in mid-February (see Turtle Release Off Coast of Thailand)
- open the Google Earth application
- in this example, we'll use Hertta's movement file for the month of March 2010
- on the Google Earth application, click "File" and then "Open..."
- locate the hertta_03_2010.kml file on your computer and click "Open..."
- the file will upload to the "Temporary Places" listing on Google Earth
- you will then "fly" to Hertta's general location off the west coast of Thailand. You will also see the map toolset on the right-hand side of the Google Earth screen. This toolset allows you to zoom and re-orient the map.
- you will also see a tool in the top left-hand corner of the Google Earth screen. This tool looks a lot like a video playback slider and—in fact—that's what it is!
- the animation slider doesn't always work consistently on Google Earth, but here's a way we've found to make the tracks play back pretty well.
- first, ensure that all the locations in the track file will be played back. The best way to do that is to make sure that the player is zoomed out all the way. Click on the magnifying glass with the minus sign inside until it is grayed out; that will zoom the player out to its maximum.
- once the player is zoomed out, you need to slide the range markers. These are the triangular icons underneath the timeline. In order to see the entire playback, you must drag the right-hand range marker all the way to the right of the timeline. When you do this, though, the left-hand range marker may move at the same time. If that happens, just drag the right-hand marker all the way to the right and the end of the timeline, and then go back and drag the left-hand marker back to the very beginning of the timeline.
- once you move the range markers to the appropriate places, simply click the start button to put the track in motion.
Please contact FieldTripEarth if you have any questions or comments about our Google Earth files.
About the author:Mark MacAllister is the Project Coordinator for Field Trip Earth.
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