Case Studies‎ > ‎Adrian Hewitt‎ > ‎

Case study tutorial: Dorsals through the days

What’s needed?

“I have identified over 300 sharks, 150 of which were re-sighted one time or more. Of these 150 sharks, 33% were observed exclusively inshore, 33% exclusive island visitation and 33% animals observed at both locations.

I was thinking along the lines of a place mark for each time an animal is sighted (using GPS coordinates). Then for each progressive sighting another place mark, so as the timeline runs it will in effect ping if that animal was present on that day. When all animals are inputted I am guessing one would expect to see some sort of seasonal pulse of movement into the different areas.”

What tools did we use?

Spreadsheet Mapper

Camtasia or

Snagit or

Google Earth Movie Maker

Spreadsheet Mapper or Fusion Tables?

Because we were interested an animating placemarks through time, we used Spreadsheet Mapper rather than Fusion Tables. The former allows you to specify a time range against each data point and this allows for animation. However, because this is a relatively large dataset, we had to create  several instances of the same sheet to achieve our goal.

Click here to view a comparison chart which will help you decide which application is right for your project.

What data did we map?

From the spreadsheet shown above, we created:

1. A layer of placemarks with simple bubbles that displays:

  • Left and right dorsal fin IDs
  • The Dorsal ID
  • The first date observed and days since first and last observation

2.  An animation through time:

  • For this we needed to define a time stamp or a time span.
  • A time stamp = single instance in time specified against a placemark.
  • A time span = a period of time specified against a placemark (xtime - ytime).

Google Earth will recognize placemarks with time specified against them, and will bring up a time-slider (as shown below). Clicking on the clock (as highlighted in the red box) will run the slider through time and bring up your placemarks as it arrives at their specified times.

Find out more about time and animation.

Getting Started: Setting up the spreadsheet to create your layer

   For detailed instructions for these steps, see the Google Earth  Spreadsheet Mapper tutorial      

1.Go to the Starter Spreadsheet and click “make a copy"

2.Enter your general information in the “start here” tab

3. Click on “share” and select  “Publish as a web page” 

4. Copy the generated link and paste it in the indicated green cell on your starter spreadsheet.

5.This will generate a network link (in the yellow block). Single click and copy.

6. In Google Earth, Right click on “My Places” and select “paste”. You’ll see a folder with a network link to your spreadsheet.  Six templates and examples are provided in the example Spreadsheet. 

You can choose one of these templates for your layer, or create your own, either from scratch or by modifying an existing template. In this case, we modified template six to the simple bubble shown below. 

To learn how to build and modify your own templates, click here. For the purposes of this case-study tutorial, we'll only outline very briefly what we did,  plus some key concepts. These are covered in much greater depth in the Google Earth Outreach tutorial, so be sure to work through that. 

Some key things to remember:

  • Within a template, you can specify static variables (information that will be the same for all placemarks) and unique variables (information that will be different  for different placemarks). 

  • Static variables are named and specified within the “template” sheet”, whilst unique variables are named in the “template x”, but specified in the “placemarkData” sheet.  

  • You’ll see all the variables specified in the “template” sheet appear at the top of the “placemarkData sheet”.  You have to specify the template number that you want the headers of to display. 

  • The balloon html layout is specified within the “Balloon html layout” box.   The static and unique variables that you specified higher up in the spreadsheet  will appear in the green box next to text box as “Unused Variables” or “Variables already in use”. 

  • You’ll see that static variables are specified as "{static_variable name}" and unique variables as "{unique_variable name}"

To modify this template to our own bubble, we did three things:

1. We changed the static variables in the "template 6" sheet as shown below:

2. Then specified the unique variables

3. Lastly, we deleted sections of the html that we weren't interested in keeping (shown in the pink below), added the extra variables that we specified in "template 6", and modified the names of variables to ones that we specified. For details on how to modify a template to suit your needs, click here

The unique (green) and static (yellow) variables are shown below with the corresponding code and bubble display. 

After this, we specified the data for each placemark in the “PlacemarkData” sheet. 

In this case we will placed each placemark in it’s own folder (i.e. We used the shark ID both as the folder name and the placemark name). This is because the researcher wanted to animate each shark separately, but still wanted to get an overall picture of shark movement through time. Placing each shark ID in the folder of the same name automatically organizes re-sightings in the same folder. The researcher can then isolate sharks by turning folders on and off in Google Earth.

We specified the GPS positions of where dorsal IDs were recorded,  the title (shark ID), the date of first observation (Paragraph 1), days since first observation (Paragraph 2), days since last observation (Paragraph3).  We slso included the URLs of the dorsal ID photographs.

Specifying Time Spans for the animation

We wanted to animate the occurrence of dorsal IDs through time – we wanted them to appear and disappear - so we used time spans and not time stamps.

To add time to your spreadsheet, you have to unhide the columns in your “PlacemarkData” sheet. To do this, scroll to the right until you find “click to unhide advanced options” and click the unhide arrow. 

This brings up the “View Look At variables” where you can specify the perspective you want for your placemarks in Google Earth  and the Time Stamp  or TimeStamp columns.

We entered the times we wanted the placemarks to appear and disappear in these columns. Make sure that you specify your times in a valid format (indicated in the highlighted blue cell).

Once you’re happy that you’ve entered all the information you want, go back to your Google earth client, and refresh your spreadsheet.  Google Earth will recognize that your place marks have time-spans associated with them and will automatically bring up the time-slider. By clicking on the little clock (shown below) you’ll mobilize the slider and your placemarks will appear and disappear as the slider moves through their specified time spans. 

Once you’re happy with your animation, go back to your spreadsheet, select “file” and “make a copy”. 

We split the data into driveby, transitional sharks 1, transitional sharks 2, inshore and island and created copies for each of these sheets. We re-named them appropriately and published them in the same way we published the "driveby" spreadsheet. 

Once we completed entering the data in all five sheets, we published them to Google earth and dragged and dropped them into a single folder. 

Create a legend

To differentiate between the different “types”of shark dorsal IDs we specified a different dorsal ID icon (each dorsal ID=different colour) in different sheets. 

To create a screen overlay, we first created a picture (we used  PowerPoint) of the dorsal fin types. We then saved this as a .png on our desktop.

Next we turned this into a screen overlay. Click here to find out  how to create a screen-overlay the quick and dirty way. 

For this screen-overlay we specified the file path, named it and specified it's size and position on the screen in Notepad as shown below. 

To create a screen-overlay animation of months

To create an animations of months through the year,  we created a screen-overlay for each month, and then assigned a time-span to it. This allowed the month’s legend to appear at the beginning of the month, and disappear at the end of the month, creating a "dynamic" screen-overlay animation. Here are the steps:

1.Create a picture for each month (in PowerPoint, for example)

2.Save as picture on your desktop/upload to a website  (e.g. google site/picasa)

3.Create a screen overlay, and choose the dimensions of your picture, and the place you would like to see it on your screen.   

4. Specify your file path or the web-address of your uploaded picture (shown in the bottom red box)

5. Specify a time-span for every month (in the top red box). It is important that you use the right time format (yyyy-mm-dd or yyyyy-mm-ddT00:00:00).

6. Save your file as a kml file (File,<<Sava as<<filename.kml

7. Repeat for all the months included in the animation.

TIP: Save your picture files in one folder, or upload to the website using the same naming convention. That way you can create your different kml files quickly by simply changing the month in your picture file path.; and the Time span. Make sure that you are happy with where you screen-overlay is positioned on the screen before you create your complete animation.

8.  Once you're done open all your months in Google Earth, place them within a single folder, and in the properties tab, unclick "allow this folder to be expanded" if you want to keep your overall folder tidy.

For our animation, we added the five network links, the screen overlay, and the folder containing the date overlay animation in one folder and saved this as a kmz file. Click to play!