Tuesday, June 12, 2012

How to Geo-Tag your Photos.

View of Kuwait City - From Dasman Block 2.
I travel a lot, and I take a lot of photos. When I start reviewing the pictures, sometimes it is difficult to remember where the photos were taken.

Some modern cameras have built-in GPS which automatically put a geo-tag (latitude, longtitude, and elevation) stamp on each picture that you take. The Nikon Coolpix AW100 is an example of a GPS-enabled camera. Other cameras (especially professional dSLRs) have support for GPS. What this means is that you can hook up a compatible GPS unit to the camera, and the camera will read the GPS data from the unit and embed that information on each picture that is taken.

But what if your camera does not have a built-in GPS or support for an external GPS? My Panasonic GX1 falls in this category. Since I want to carry this with me on my trekking trip to Kashmir, I thought it would be a cool idea to geo-tag all the pictures that I take during the trip, in order to make it easier for me to sort them out later on.

Here is a step-by-step guide on how you can geo-tag your photos.

1. Get a GPS Logger: You have many options available. Starting from the expensive dedicated GPS loggers, to the free option of using a GPS enabled smart-phone that most of us own today. For my Kashmir trip, I might get a dedicated logger such as the i-gotU GT800 (cost $99). The advantage of dedicated GPS loggers is that they work off AA batteries, and require very little setup.
For my experiment, I used my Android smartphone (Samsung Galaxy Note). I downloaded a free app from the Play Store (unimaginatively called GPSLogger). The app runs in the background, recording geo-points at regular intervals (which you can customize). I set mine to record every 1 minute.

GPS Logger on Android Smartphone.

2. Synchronize your camera & GPS Logger: This is very important. Check the time on the GPS logger, and make sure that the camera is set exactly to the same time. Keep in mind that the clock in the camera is not very accurate, so you should check it every few days to ensure both are in sync.

3. Start the GPS Logger & begin shooting: Make sure you turn on the GPS logger (or your app), before you start shooting. The GPS logger will keep track of your route, and record it in the log file.

4. Match the Pictures with the GPS data: Once you download all your photos from the camera, you will need to download the GPS log file. The standard format for storing GPS data is GPX, but there are other formats available. Also, if you purchased a dedicated GPS logger, it will come with its own software to do the magic of matching the picture with the exact location where the photo was taken.

In this example, I used a free utility called "GeoTag". You can find all details about the program, and the exact requirements for running the program here.

The free GeoTag software in action.
You simply run the program, load the images and then load the GPX log file, and the software does the matching and links the correct geo-coordinates for each image. It is as simple as that.

You can even view all the images on Google Map.

The GPS logger nailed the location. I was on that bridge when I took the picture.
Tools such as GPS Visualizer also allow you to check the entire GPS log, as shown below
GPS Visualizer read the Log file and plots the route on Google Map.
When you upload a Geo-tagged image to popular photo-sharing site such a Flickr (which is geo-tag enabled), it will automatically identify the location and set the right location for each image.

Flickr identifies the exact location of the photo.
Now your Flickr photo not only has Geo-coordinates, it has the exact location name and country mapped to your photo.

The Photo is mapped to the exact place, and country.
And that's all there is to it. I don't know why I waited till now to start doing this - but one thing is for sure. All my future photos are going to be geo-tagged.

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