F/Stop Media Photography

One of the hot topics in Digital Photography in recent months has been Geotagging. The confluence of Digital Images, Online Mapping and GPS devices and services such as Flickr have lead to an upsurge of interest, use and software to support this need. Cameras, such as the Nikon P-6000, are beginning to incorporate GPS chips, mobile phones are increasingly gaining GPS chips, and there are several additions to cameras that add the facility to Geolocate your images. Geolocation can be performed in several ways. The first is that the camera can automatically write the map position into the EXIF data of your files, this occurs with onboard or built-in devices. The second is to use a GPS tracking device that will record your positional information as you take your images, back at base you have to marry up the log file with the images you shot. This needs the clock of the GPS device to match the camera’s time (you can insert a time offset if you have forgotten to do this before a shoot). It also needs some third party software to match up the log and the images and combine the information into the images’ EXIF. The third way is to use an online mapping tool such as Google Earth or Yahoo Maps and, again, use some third party software, or web service to position your images. Lightroom supports images that have been Geotagged, but there is not a convenient way to achieve this in-app. However, Jeffrey Friedl has given Lightroom users “Jeffrey’s GPS Support” which lets you import track logs from GPS devices and match them to your images. First of all you will need a GPS device. The market is booming and a trip to your local hiking store or a check online will overwhelm you with choice. Before making a purchase you will need to ensure that the device will create a track log as a file, that you can connect it to your computer and that your computer is compatible with the device. Macintosh support is slightly rarer than Windows support, although this is changing as the devices become more sophisticated. I have recently started using the Apple iPhone 3G as my GPS device. Reports have been very favorable as to the accuracy of its GPS information, so I was keen to see whether there was any software that could transform the GPS device into a useful tool for the photographer. Other phones have this capability too. A quick trip to the Apple App Store and some research offered up Felix Lamouroux’ Trails, which allows you to record, import and export GPS tracks using your iPhone. According to a German article Trails beats the Garmin Edge 305 as a GPS device. The Garmin costs approximately $200; Trails $1.99! Trails will track your progress on a shoot, saving a GPX file of the waypoint information, which you can then set to email to you when you have finished. The first screen you encounter is the List of tracks you have recorded. I have one from January 3, 2009 on a trip to Wormley Woods in Hertfordshire, UK. To create a new track you would hit the plus sign.

Tap the Settings button to setup Trails for a photo shoot. There are a set of four Presets for you to use, unfortunately Photography isn’t one of them, but the nearest equivalent is Hiking. This gives an accuracy of 150m, which should be enough, but you can always adjust this down to 20m. This results in a larger file and fewer outliers (points that are guessed).

As using the GPS on the iPhone sucks the battery life, it is advisable to turn off the “Live Map”. Other recommended battery savers are to turn off WiFi and 3G and to lower your screen brightness, which can be done in the iPhone’s settings. The only other pieces of information to enter are your email address and or your EveryTrail username and password. EveryTrail is a GPS community, where you can share your GPS track information and journey information. Once you have finished tap Done. Before use, the three things to check are, that you have a fully charged iPhone, that you have turned off Auto Lock in your iPhone’s settings and that the iPhone’s clock and your camera’s match. As mentioned, you can adjust the offset later, but this speeds up the workflow. On the “My tracks” screen, tap the + button, enter the name of the track and a quick description. Then press Save. You are taken to the recording screen, and when you are ready tap the Record button. Trails will active the GPS and lock on to a satellite and begin recording your trip. Once you have finished, slide the slider to stop recording. The screen shows you all the information about your trip, as well as the list of waypoints. You can interact further with Trails by viewing your route on Google Maps within the application, as well as viewing an altitude profile; for this press the globe button in the bottom tab bar.

What we really want now is the GPS information in a format that we can use to position our photos. Tap the right hand share button in the bottom tab bar, this offers the choice of Exporting your file to Email, EveryTrail or TrailRunner; tap Email. In a few moments check your email for a mail from Trials with an attached GPX file. Make sure your spam filter doesn’t block emails from Trails <no-reply@lamouroux.de>. A quick look at this file in a text editor shows that it is an XML file of your waypoints. You can use this file with a variety of pieces of software. The basic concept of each of them is to select the images from your trip, import this GPX file and automatically match the time of the waypoint with the time the image was taken. Third party software can be bought specifically for this, such as HoudahGeo on the Mac and RoboGeo for Windows, they also offer the more manual GPS tagging by linking to Google Earth and positioning your image on the globe. This method is less accurate and does depend on the quality of the map and your memory of where you were! For this example, we shall look at Jeffrey’s GPS Support Plug-in. Jeffrey is a Lightroom tester and Plug-in developer and has given many free Plug-ins to the Lightroom community. He is also the author of the de-facto standard book on regular expressions, Mastering Regular Expressions. Download and Install the Plug-in as described on his Plug-in page.

Select the images from your photoshoot. From the File menu, select Plug-in Extras > Geoencode…

From the tabs, select Geoencode from Tracklog. Locate your GPX file with the Browse button, enter your Timezone and enter any time compensation you may need if you didn’t align the clocks of the GPS device and the Camera.

Then click Geoencode Images and in a few seconds your images will be processed and you will see the results displayed in the Metadata panel in the Library.

You can also grab one of Jeffrey’s other Plug-ins GPS Proximity Search, this allows you to find Geoencoded images in your Lightroom Library that are within a specified distance from a location you choose. Returning to the GPS Plug-in. What has been achieved so far, is to locate the images and add information to the Lightroom interface. But more useful still is to write this data to the EXIF information of the image. One of the other tabs Write Data Back allows you to achieve this. Select the Tab, and you will see a list of instructions explaining the sequence you need to follow to ensure the EXIF is updated.

First, you need to save the Image Metadata, this is to write any Develop settings, Keywords and IPTC metadata you have previously created for the image. This is achieved, by selecting all the required images and either selecting Metadata > Save Metadata to Files, or press Cmd/Ctrl-S. Then in the GPS Support Plug-in, click the Write Shadow Data to Files’ Image XMP Sidecars (note the wording may have changed by the time you read this), following the success dialog, you got to the next step. This is to read the updated Metadata back into the database and EXIF. To do this, select Metadata > Read Metadata from Files.

Now you will see the information in the EXIF section of the Metadata panel. The arrow button next to the GPS information will take you to the Google Maps page for this location. Pressing Option/Alt will take you to the Yahoo Maps page for this location. Applications such as HoudahGeo and RoboGeo use the same basic procedure and all three mentioned here allow manual positioning with Google Earth as well. (via TechOn Japan)