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Thursday, 28 August 2014

Geotagging photos using GPS tracks, ExifTool and Picasa

I take a lot of photos while trekking, and most of the time I'm also carrying a GPS with me. As my camera don't have a built-in GPS, my photos are not geotagged while shooting. Luckily, this is an easy task if you've kept your GPS logs from the trip. 

I'm still very happy with my Garmin GPSmap 60CSx that I bought 7 years ago. By changing the setup, the GPS allows me to automatically save the tracks to the memory card. I get one GPX file for each day trekking named with the date. I can easily transfer these tracks to my computer or smartphone with a cable or a card reader. 

Before I converted to Mac, I used GeoSetter to geotag my photos on Windows. Now, I want to do it on the command line using the great ExifTool by Phil Harvey. I installed it on my MacBook using Homebrew:

brew install exiftool

After copying my GPX file to the image folder, I'm simply running:

exiftool -geotag=my.gpx ./

If you forgot to sync the camera and GPS time before your trip, you can use the geosync-option to fix it: (60:00 = 60 minutes):

exiftool -geotag=20140329.gpx -geosync=-60:00 ./

You have a lot of options, so make sure to read the "Geotagging with ExifTool" documentation. ExifTool is modifying the Exif headers of your image files, storing the location data in the same file. 

To see the result on a map, I'm using Picasa.  


Click the map pin button (bottom right) to see the map. If the positions are not shown on the map, try to right-click the image folder and select "Refresh Thumbnails". 

If you don't have a GPS track you can always use Picasa to manually geotag your photos. 

Be aware! I just learnt that social media sites like Facebook, Twitter and Instagram removes the Exif data from your images. Google+ don't. 

Now, how can you display the photos on your own map? It will be the topic of my next blog post. 

3 comments:

Anonymous said...

I use my tracks on mac, as i also miss geosetter.
http://www.mytracks4mac.info

exiftool i did not try yet but i will do.

What about pic services like flickr or 500px ? Do they also remove geotags?

Bjørn Sandvik said...

See this list:
http://www.embeddedmetadata.org/social-media-test-results.php

Pepper said...

There is need to install homebrew to get ExifTool. A Mac DMG installer is available from the ExifTool home page. Plus, this version is likely to be more up-to-date than the version you get via homebrew.