Blog

First steps with geotagging

A large amount of data is attached to a digital image when its captured by the camera. Information hidden against the image will reveal how the photographer had the camera set when they took the image as well as other information which can be added by the photographer such as personal information, keywords and titles which will stay with the image forever - or until some activity strips it all out. One of the things that can be recorded against an image is the location that the image was taken from. This is recorded as GPS coordinates and would normally require the camera to know where it is at the time the image was taken or it needs the photographer to add this information later. I've never really felt a strong need to record this because I don't have the necessary technology to embed this information automatically in camera and it would be yet another step that I don't really need in my workflow. With the arrival of Lightroom 4 their are new features within the maps module that allow this type of information to be attached in post production quite simply so I thought I'd try this out and share with you how I did it if you were tempted to try it yourself.

To try out some geotagging I use Geotag Pro

The first thing you will need is something to periodically record your GPS coordinates. There are dedicated devices which can do this for you, but I don't have one of those. Instead I do have a smart phone. Or to be more precise an iPhone - I assume that there is software available on other platforms to support this as well. Having a quick look on the App Store, I settled on an App called "Geotag Photos Pro" at the princely sum of £2.49. Anything that creates files with an extension of ".gpx" should be fine. This app allowed me to track my location using the inbuilt functionality of my phone. For my test, I packed my daughter up into her push chair and set off for a walk along the Holme valley with my compact Fuju X10 camera.

Step 1: Synchronise the time of the phone and the camera

This is an important step otherwise you'll have to offset your image's timings. Don't be tempted to think that it's enough to synchronise once and forget it in the future, the clocks inside cameras aren't particularly accurate and do drift even within a week or two sometimes.

Step 2: Set up your geotagging software

This is going to depend on the software you're using. With Geotagging Photos Pro, a trip is setup which is given a name and a interval. With each interval, the software checks your location and records it in the phone. For my first attempt I set this to a 5 minute interval. My thinking was that I don't walk especially quick (it's pretty hilly and I'm very pedestrian when I'm out on a stroll). Also, the more often the phone checks your location the quicker the battery will drain. I don't personally see a problem here unless you're going to be out for an extended period. My battery didn't seem to suffer too badly from running this software in the background on my phone. I was still able to check mail and use the phone with the software running. Just remember to stop recording when you're done.

Step 3: Take some photos

While out and about I kept the phone in my pocket which is something you may not be able to do with a dedicated GPS tracker because that needs to maintain a line of sight link to the satellites  they use for positioning. The phone however can rely on the cellular network to work out a position if it can't see a satellite. I am guessing it could be a bit of a headache if you're out of range of a phone network in which case you'll need to keep your phone out somehow. Perhaps if you're out in the middle of nowhere there'll be less need to worry about light fingered passers by so it could go into one of those net pockets camera bags and rucksacks seem to have? Anyway, the only time the phone complained was when I was sat on Longley's Ice Cream Parlour and Coffee shop where the phone couldn't get a signal.

Step 4: Offload the GPS coordinates onto your computer

The easiest way to get the GPS file off the iPhone is through iTunes file sharing.

This again will depend on your software and hardware. I find that the easiest way to get files off the iPhone is through the app's file sharing link in iTunes. It is possible to get the app to email the file as an alternative approach which some might prefer.

Step 5: Offload the photos into Lightroom

I attach my GPS coordinates before performing any other modifications to the images. Some software can strip the metadata from the image or copy across metadata in conversions so it's best to get all your metadata in as soon as possible so it gets carried through the whole post processing workflow.

Step 6: Go to the map module

This is a new module in Lightroom 4 and offers features for tracking the locations in your photo collections. Here we can associate the gpx tracklog created by the Geotagging software to photos.

Select a folder from the Library module before switching to the Map module because it is only possible to select collections once inside the Map module.

GOTCHA: The Map module in Lightroom only displays collections. If the images have just been imported, they won't exist in a collection. While it would be OK to move them into a collection before selecting the Map module, it's easier to simply select the folder in the Library and then move to the Map module. The folder will still be displayed in the filmstrip and will remain active unless another collection is selected.

Step 7: Associate the GPX file to the images

Select the squiggly button to import a GPX file into Lightroom.

WIth our images in the filmstrip and our GPX tracklog file ready on the computer, it is possible to associate the two files. On the toolbar below the central panel there is a squiggly button which is where you can select the GPX file to import.

After the GPX file has been imported, it becomes available as a track that will be displayed on the map.

With the track and the photos selected, an option will be made available to Auto-Tag the photos.

Once the file has imported, it will become available as a track in Lightroom. The journey itself will be displayed on the map without necessarily having any photos associated to it. Now it is possible to attach coordinates from the GPX file to the photos. The photos must be selected first. After which select the squiggly button again and the option to "Auto populate selected photos" will be visible.

The folder I imported had about two hundred images on, of which only a few were from this walk. Lightroom applied some tolerance and tagged 57 of the images from the folder. It did this correctly and the map now displays indicators to show where I have images from the walk. Even though the actual coordinates will be based on the last recorded location it seems accurate enough for my simplistic purposes. The accuracy could also be increased by taking more position in the tracking software.

Having tagged the photos, they display on the track. To the right it is also possible to see the metadata for the image showing the GPS coordinates, altitude and location.

The extra information now recorded against each image can be seen in the metadata showing to the right of the map. Here the GPS coordinates for a selected photo can be seen along with the location as text fields and the altitude. Each image that has GPS coordinates acquires a small signpost indicator in the thumbnail.

It is now possible to organise images based on the additional information visually with the map of using filters etc. Having images tagged with GPS coordinates is a useful thing to do and can help with the management of images or simply remembering where you were at the time. While there are more dedicated solutions out there, this seemed to perform well enough for my general purposes and assuming that you have a smartphone and are using Lightroom 4 then the the only additional outlay is for the app. If you're not using Lightroom then it's still possible to associate tags your images, it just means using an additional piece of software; but that's another story.