WHY BOTHER WITH PHOTO TAGGING / GEOTAGGING?

Each year we go on a couple vacations and come back with 100’s, sometimes 1000’s of images. One of the most tedious steps is recreating our travel route and cataloging images by location. I do this using Google maps and retracing our path along roadways and guessing where we stopped by zooming-in and using Google’s street view. The process takes many, many hours. And when shooting locally and driving through the North Texas backroads, I spend most of the time almost lost. This is wide-open in country fields, and many of the roads are just dirt or gravel. In car navigation has helped immensely, but that does not help much when it comes to putting the location data into the raw camera files.

I have thought about geotagging before and each time I looked into the devices, the applications and the workflow - it was overwhelming and intimidating. In principle it is simple:  a device logs your location every X number of seconds or Y number of feet. The data is stored in a log file. Back at the computer the log file is downloaded from the device and uploaded into a photo tagging application. The application opens up the pictures files and embeds the GPS coordinates whose time stamp most closely matches the image’s create time stamp. It is simple, but the caveats include - what format does the GPS device use for its log file? What raw image file formats does the geo-tagging software support? How well does the GPS receive its signal? What is the GPS unit’s battery life?

GEOTAGGING WITH THE CANON 1Ds MARK III dSLR

I selected the Sony GPS-CS3KA because it has a small LCD display for configuring the device. Some of the cheaper devices just have a couple LED lights and/or require configuration via the computer and USB connection. Before buying the Sony, I found out that its log file was in the “NEMA 0183 Sentences” format. That format can be converted to .GPX (a text file format called XML) which then can be read by various software applications. On the device side of the equation, the Sony unit looked like a workable solution. The next part of the equation was finding an Apple OS X application that supported the Canon CR2 and Leica M9 DNG files. I selected GPSPhotoLinker.

GEOTAGGING WORKFLOW

Geotagging the images is fairly simple, but there are a number of steps involved. For now, this is my workflow:

1. 1.Turn on the Sony GPS-CS3KA and set it to the correct GMT offset for the current geographic location.
   

2. 2.Turn on the camera(s) and make sure their clocks are synchronized with the GPS unit. The Sony gets its time from the GPS satellites, so the in-camera clocks are set to match the GPS unit.
   

3. 3.There is a menu option on the Sony unit to erase its internal memory. It has 128 MB of internal memory and a 4 hour trip will generate about 500 KB data. Each log has a date stamp, so deleting the old data is not necessary. I do it just to keep things simple.
   

4. 4.A standard alkaline AA battery lasts around 16 hours, so I turn on the Sony at the start of the day.
   

5. 5.At this point the Sony GPS device is in “set it and forget it” mode. I keep it attached to the camera bag strap. The Sony unit has a 3 bar signal strength indicator, so that is helpful.
   

6. 6.The rest of the day is just like any other day. When done shooting for the day, I turn off the Sony GPS unit to save battery life.  The LCD is also has a 4-segment battery life indicator.
   

7. 7.Back at the computer the Sony GPS is connected to the computer via a USB cable (included with the Sony GPS unit). The GPS unit appear in Finder like a USB thumb stick.
   

8. 8.Then I create a folder in the documents folder and named GPS Tracks and copy the Sony GPS log file to the folder. It is best to work with a copy of the original log file in case something goes wrong.