How to #unzip a #KMZ file


Screenshot of my KMZ file

In this tutorial, I showcased how to unzip a KMZ file.  Here is the video:

The significance of this tutorial, if you recall from my Part 2 of Capture Your Tracks , when I was not sure as to how much accuracy was actually captured by the application.  It took me a few weeks to ponder, while I worked at my day job (sorry boss…but you can’t do much about my imaginations of GIS fascinations…).  I recall that the elevation and travelling speed outputs were quite live, and even when you “Record” there is a live moving average read out.  So I concluded that while the individual points were not shown, like my NovaTel GPS unit (that’s Canadian made eh), My Tracks was still capturing the data.

So if I have you completely lost, we are talking about the data I collected in my Google Drive, when using My Tracks offered by Google for Android.  Where I did Part 1 Capture Your Tracks (and part 2 is in the link in the paragraph before).  Using the KMZ file uploaded to Google Drive using the App’s export tool, I wanted to learn more about the file.

So now you’re caught up, let’s look at the image that I uploaded in this blog entry.  Now, I’m not a fan of how un-formatted the file was, but it still gives a lot of information.  In the first few lines, you have the commentary section, giving some information on the version, how it was captured, name of author.  Following that, you have what are markers and the kml code pointing to images in the Google Earth installation, so you can have the graphical display of your start and end of data capture.  You arrive to three lines then a break and then it continues.  This is where I paused the Record function then resumed data collection (partly because with running this application and recording my tablet, my tablet was struggling). * Ahem* that’s also the reason why the audio went out a few times, its the tablet processor struggling.  I did take the Power Saver Mode off, but even then, the tablet was struggling to video capture the screen while I was running My Tracks.

So this continuous section of data shows us a few things.  1) It shows the datetime information.  2) Elevation, denoted in notation like “504z” which I can only assume is meters above sea level, z being the z axis. 3) You have the coordinates, x and y.


KMZ file showing x, y, z coordinates as well datetime

Now you’ll also notice that the intervals are almost every second.  If you recall, prior to recording the video, I made my settings really fine so that I can capture the most data possible (that’s also probably why my tablet was complaining while I was recording the video).

As we follow the file, there is a section for the speed.  You’ll also notice the name label (“<gx:SimpleArrayDataname=”speed”, we also have bearing and accuracy.


KMZ file with speed, bearing and accuracy.

At the end is something really cool.  The program wraps up and write the last bit of information that really optimizes the Google Earth experience, which is the total distance, the moving time and ect.  When you import this into Google Earth it presents itself as a little info bubble on Google Earth.


KMZ info on distance travel and commentary information displayed in Google Earth.

All-in-all, I was quite satisfied within using My Tracks, my ignorance prematurely got me.  Just reviewing the data, once you unzip the KMZ, you can really see this My Tracks application capture A LOT OF DATA.  It’s really cool.  Now, I’, not sure how much accuracy the data holds.  I guess, my next thing to think about while I’m sitting at my day job (sorry boss) is what the accuracy values represent.  And what the bearing values mean.  In my capture, Accuracy was represented in a double format ranging from 3.9 to 9.0.  Bearing bounced around from 101.0 to 106.0.

So thanks for reading my little fun experience with how to Unzip a KML files and really interpreting the output from My Tracks.

If you found the video interesting, be sure to LIKE the video, it really helps other YouTubers find the video.  I’ll see you in the next video!





Capturing Your Tracks on Android

Learn how to #Capture Your #Tracks, using #MyTracks and #GoogleEarth.  To start the new year, we are playing with some freely available apps and making our own data.  As an extra bonus, you don’t need to be in front of a computer, since this is a tutorial using your Device and an App that you need to pre-load.  My Android-based tutorial does not require internet or data.

If you find my tutorials useful, Thumbs Up my video.  It’s always nice know someone found the video useful and it helps other users decide if the video is any good.


Live read of my average speed and elevation while capturing data.


Elevation and Speed read out

Today, I’m sharing you my fun adventures in demonstrating how to record your location using your own device.  My tutorial was Tracked right in Verner, which is Northern Ontario.  You know, where all the people live in Igloos most of the year (joking….seriously I’m joking…but it gets really cold there).  To do this tutorial, you need:

  1. GPS enabled device (tablet, cell phone)- note Data is not a requirement
  2. A mode of transportation (foot, bike (hopefully in tandem), vehicle).
  3. And pre-installed application.

So there are three ways you can do this Capture of your tracks.  One way is to use a GPS unit like a Garmin, where you can export you data.  Please review the instruction manual for you device.

The second way is to use an Apple iPhone, and a trusted software you can use is MotionX-GPS.  This is a software I found trusted for iPhone.

The third way, and the way I will be demonstrating is using My Tracks on Android Samsung Tab 4 (Tablet).  Just a disclaimer, I chose to use My Tracks because its a Google software.  To some extent, I have trust in a Google software.  There are many others, just use with caution.  Considering the amount of data being collected, you want to be careful.  Especially downloading an application to your phone or tablet, a device you may use for personal photos, emails, phone calls…you want to make sure you aren’t opening yourself to cyber attacks or something.  So here is Part 1 of my Tutorial:

Once downloaded, I needed to enable “Location” or the GPS capabilities on my android device.  What’s cool is that you get GPS communication without subscription and no Data required, its really cool!  Now on cell phone, it may be different, your GPS may be also influenced by cell towers, where you location is constantly triangulated between cell towers for accuracy.  Fun fact, Samsung Tab has GLONASS capabilities, but that feature ain’t supported in USA and Canada…hehe.  Here’s a link to the specs if you’re curious.

Once its set to go, you can press Record, that will be located on the left side of the application, its a big Red Button.

While you’re recording, I thought it was cool how you can record even markers by manual entry or photographs.  For example you can take a photo at the start, middle or end.  What’s nice is that it pulls your full featured camera (not the very basic camera on your screen before you unlock your device).  This is great, because if you’re driving, you may want to change it to action mode since you driving (otherwise you get a complete blurrrrr-not cool).

I do have a Disclaimer for any users using this while driving, make sure you aren’t operating a vehicle.  I was very fortunate, I had someone driving the vehicle while I was capturing.  You should never be operating a vehicle while playing with a device, devices can be a distraction.  More so, depending where you are, fines can very from place to place.  In Canada we have some hefty fines.

Once you do a good length and you are happy with what you recorded, you can stop the recording and you can export it to your Google Drive.  Now, if you want to view in Google Earth, Google Earth really likes using Google Drive, so you may need to use Data or access Internet.  The beauty of My Tracks is that you can capture without Data and upload later.  Plus, if you want to view on Google Earth, you’re going to need Internet… As a warning, if you are uploading to Google Drive, double check your security sections just to be safe.

Now, when I had access to Internet, that’s when I started viewing my data.  Here is Part 2 of my tutorial:

So I uploaded to Google Drive and launched Google Earth right on my Android device.

So you can adjust settings on the accuracy in your device, and thinking about it, this is how we get that lovely elevation read out and play-by-play statistics.  But when I opened it in Google Earth, I was disappointed, the default export appeared to only show the start and end of my data collection, not the interval collections in between.  So a bit disappointed.  What I might do is export the kml (or kmz) and see how the data looks like some time.

As a special treat, I had a kml of my own Novatel GPS unit that runs at 20hz frequency, just so you can see how high resolution data looks like.  That’s the type of output I was hoping for, so I’ll have to make some time and poke through my data and see what is happening with My Tracks.

So if you found this tutorial, install an App, Track your travel and share with your friend.  I challenge you to snap shot a nice scenic route for a jog with your favourite stopping points (just make sure you only share with trusted friends…).

All-in-all, I hope you found this tutorial fun.  I’m looking forward on building on this captured data for another tutorial, so stay tuned and happy GIS-ing!