Animal tracks and collar data in Google Earth

Posted on September 19th, 2011 in General,Google Geo Tool Blog Series,Google Geo Tools,Workshops by Alta

In many conservation research and management projects, practitioners follow animals to see how they use the landscape. This sort of  information is usually collected by researchers following their study species with a GPS unit/field data kit or by GPS collars and tags attached to individual animals.

In this blog post, the next in a series on Google Geo tools to complement our workshops, we skim the surface on how to visualise these sorts of data with Google Earth (mostly). We cover both data that comes in a GPS file format (e.g. .gpx files) and data that, as is typically the case with collars and tags, are in tabular format (e.g. .csv or .xls files).

What’s so great about animal movement data in Google Earth?

We follow animals to understand how they interact with and move through their environment. The data collected for this inherently comprise both spatial and temporal information – information that can be used to faithfully reconstruct a particular animals’ movement behavior in Google Earth – a virtual representation of that animal’s environment. The result? Very powerful visualisations that can help researchers, managers and other stakeholders better understand movement of individuals and populations and hence allow them to make more informed conservation decisions.

Google Earth and spatiotemporal data

When you open a file in Google Earth which contains features that have time associated with them (as time-stamps or time spans), it will automatically recognise this time element and bring up the time-slider (shown below).

You can read more about the time-slider, one of the tools you can use in Google Earth to animate data, in this Google Earth user-guide article. In short – the time-slider picks up the earliest and latest date/time associated with your data and then runs through segments of that time line, as defined by the two grey arms on the slider. Google Earth will show the selection of features that has time-spans/stamps that fall within the time-segment that the slider is highlighting at any given time.

Tracks in Google Earth

When you’re following a study species in the field, you’re probably not only collecting waypoints, but also tracks (read this article for more on how to record tracks on your GPS unit and mobile smartphones for use in Google Earth).  A track comprises both time-stamped points (so you can animate segments of it at a time) and a line element (so you can fly along it).  Although they are made up of points, tracks only have one placemark associated with the entire line. You can customise your track with an icon or even a 3D model, and Google Earth will move that icon/model through the landscape in the same way your followed animal did.

To import a track (and other GPS data) from your GPS unit into Google Earth is more or less as simple as opening the file through the File>>Open or File>> Import option and you also have the option of importing a file directly from your unit and in real-time. This  Google Earth user guide article has more information on how to do that.  Once you’ve imported your track you can go ahead and view it by using the time-slider and create a tour from it, just as in this blog post example.

A great feature to help you understand how your study animal moved across the landscape is the ability to show  the elevation profile of your track (right click on the track and select “elevation profile”). This will not only profile the landscape, but will also allow you to view other information (like speed, as in the baboon track example shown below) at any point across that journey.

For more on GPS waypoints and tracks, and what you can do with them, view this Google Earth Outreach tutorial and this Google Latlong blog post.

What about tabular data?

Data from a GPS are really easy to import into Google Earth, but often times, especially with collars and GPS tags, the data comes in a tabular format, not as a GPS file.  These data are a little trickier to get into Google Earth, especially if you want to animate your points. They’re also more difficult to turn into tracks, although you can do this in GIS packages (see this post for a great example), using conversion packages like GPS Visualizer (though this doesn’t produce great results in our experience) or by changing the KML code directly. Once your data have been imported into Google Earth, you can view and visualise it in the same way as for the GPS files.

We’ll focus the rest of the post on importing and animating points in a tabular format:

Importing and animating your tabular data

There are a number of tools you could use to get your tabular GPS data in Google Earth – different ones are better depending on how much data you have and what it is you would like to visualise (you can always mix and match!).  By no means an exhaustive list, here are a few options:

Option 1: Google Earth Pro

In Google Earth Pro you can import .txt and .csv files simply (file>>import or file>>open), as long as your GPS points are in a format supported by Google Earth. Importing your data in this way won’t animate, though, as time values are included as descriptions, not time-stamps.  You can import any number of points, but more than 5000 will result in a slower performance.  Google Earth Pro is not free, but if you can apply for a free grant as a nonprofit or educational institution, or try a free 7-day trial.

Option 2: Fusion Tables

You can import almost any kind of common format tabular data into Fusion Tables, and there is no restriction on the number of points in your table.

Once in Fusion Tables, you can filter your data on categories and style, visualise and map accordingly, so this is a great option if your follow data also include variables like foraging preferences or social behavior.  You can also merge your table with other datasets, create attractive looking information windows for points and export your data sets to Google Earth.

The one thing you won’t be able to do though, is animate your waypoints with the time-slider in Google Earth (your time values will be included in your information bubbles, but not as a time stamp).

To get started with Fusion Tables, see the three relevant tutorials on the Google Earth Outreach tutorial page, or the Fusion Table help centre.

Option 3: Spreadsheet mapper

Whilst Spreadsheet mapper doesn’t have as many options for data management, manipulation and visualisation as Fusion Tables, and only allows for import of 400 data points at a time, it does, like Fusion Tables allow users to create attractive information bubbles for points. Unlike Fusion Tables, it also allows you to specify time stamps against points, which means that you can animate your data in Google Earth.

We used spreadsheet mapper to create an animation of shark dorsal IDs that were recorded through a summer off Gansbaai, South Africa.  For this project, the researcher both wanted to get an idea of overall movement of known sharks through time, as well as be able to view specific information about individual sharks in the pop-up windows. You can read the case study for this project here.

Option 4: GPS Babel and GPS Visualizer

GPS Babel and GPS Visualizer are free online tools that allow you to convert various formats of GPS, text and KML files into each other.  Both allow several different options for customising waypoints and are also great for combining multiple tracks into a single one (something you can also do in the KML code). They’re not the best options if you’re looking to make attractive information bubbles, though. With both these tools, converting a tabular dataset into a GPS or KML file is mostly as simple as uploading a file and pressing a button, but it is worth reading through this help article to get an idea of what is possible and to ensure that your data are in the right format.

Other Options:

There are GIS packages and many other online applications that can help you get your GPS track into Google Earth – here is a list of more tools if you’re interested in exploring further and/or the above don’t meet your needs. Most GPS management software applications (like MapSource) also offer the option for manipulating GPS data and exporting it to Google Earth, although it’s sometimes better to use the saved GPS files from these applications and add it to Google Earth yourself. The trick is to find what works best for you!

In addition to GPS units, many of you use field data kits like CyberTracker or Open Data Kit for Android. For FDKs like CyberTracker you can visualise your resultant data in the same way you would other GPS files and tabular data, as described in this post. ODK offers some great options for visualising field data and is well integrated with Fusion tables. You can get started with ODK in this Google Earth Outreach tutorial.

A real-life example of tabular tracking data:

The data below is a sample of data collected by Alison Kock of the Save our Seas foundation. Alison and her colleagues manually tracked a great white shark over an afternoon and a morning in December 2009. Alison is interested in (amongst other things) how sharks move in False Bay in different seasons. In winter, sharks typically spend more time closer to the middle of the bay at Seal Island, hunting seals, whilst in summer, many spend more time inshore. What do they get up to there? Well, sometimes, as this track shows, not all that much….

This dataset was in a tabular format, so before we could see it in Google Earth, we had to turn it into a GPS file first. We were really only interested in visualising the movement of the shark through time, so we used GPS Babel to convert our .csv file into a .gpx file and opened this in Google Earth. We also subsequently went into the KML code to turn the points into a track (the track is not included in the animation below, but you can download it here).

When we opened our .gpx file in Google Earth, it recognised the time stamps in our file and brought up the time-slider, which we used animate our points and track. Although this made sense to us, replaying the track in this way didn’t tell that much of a story without the context of  time, scale and place.  So we created a Google Earth tour to guide the narrative of our simple data story. We then made a video of that tour (shown below), so we could share it on this website and for Alison to use in presentations. We also uploaded the Google Earth tour we made (download it here for best viewing) to her project bubble on the MAPA Google Earth layer.

 

Remember that you can associate any KML or KMZ files with your project on the MAPA layer and/or embed YouTube videos in your project bubble. Simply log into your account, open your project, and upload your file. You can add YouTube videos by clicking on the Video tab, pasting the video embed code and associating that with your project.

We hope this post gives you some ideas for your GPS data – let us know what you come up with and don’t forget to upload it to your project bubble!

 

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