15 Months, 16 countries, and 1000s of photos taken on the road – from boats, trains and buses, and on horseback – all of them geotagged and many displayed with GoogleMaps. How do we do it all?
We’re going to tell you in a three-part series – starting now.
We are frequently queried about our photography and the topic of geotagging. The conversation often begins with “What's that device with the blinking light hanging from your camera bag?” The questions continue:
- What is geotagging?
- Why do you geotag your photos?
- How do you geotag your photos?
- How did you get those maps at the bottom of your photo pages to work like that?
We thought a case study on geotagging would be useful for fellow photographers, travelers and technology geeks alike. We’ll publish it in three segments:
- Part 1 (this article) is intended to explain what geotagging is, why you might consider doing it, and which GPS device we use, the Sony GPS-CS1 (Sony GPS-CS1KA). This section is for readers new to the concept of geotagging.
- Part 2 addresses the technical nuts and bolts of taking geolocation data from the Sony GPS-CS1 (Sony GPS-CS1KA) and embedding it into the EXIF data of a photo. We will discuss the hardware and all the various software (Sony GPS Image Tracker, GPSBabel, and GPSPhotoLinker) that we use to efficiently geotag large groups of photos.
- Part 3 covers how to upload your geotagged photos using PictureSync and what you can do with a geotagged photo, including using Google Maps to interactively display where the photo was taken.
A note on naming conventions: We actually use an earlier model of Sony's GPS device, the Sony GPS-CS1. To remain current, we will refer to the device as Sony GPS-CS1KA, the updated (yet functionally and technically similar) model.
What do you mean when you say a photo is “geotagged”?
A digital photo is geotagged when location data (latitude and longitude coordinates) are added to the digital file alongside the photo’s existing EXIF data. EXIF is the data in a digital photo file that describes things like the kind of digital camera used to take the photo, the date and time when the photo was taken and the conditions under which the photo was taken (including shutter speed, aperture, etc.). You can find a sample of EXIF data on the right-hand side of one our individual photo pages, under the “Photo Tags” section.
The basic steps of geotagging photos:
- Collect digital location data (latitude/longitude/time coordinates) using a GPS device.
- Based on time stamps, match your photos with the location data logged by your GPS device.
- Embed the matching location data in the EXIF data of your photos.
Why Do We Geotag Our Photos?
As a matter of practicality, we’d like to know where each of our photos was taken.
“Why not jot this down on a piece of paper somewhere?” you might ask.
A valid question perhaps, but considering that over the course of this journey we are using two cameras and taking 1000s of photographs across dozens of locations, this is not a practical option. While we do take notes, we sometimes miss the name of a village or mountain. In the context of extended travel, the process of manually associating accurate location data with each photo becomes a colossal nightmare.
Geotagging our photos is a critical step in accurately documenting our journey. If we use a GPS device and some freely available software, we can batch process and associate our photos with detailed location data (within about 50 meters).
We also use our photos to help us tell a story about our experiences. However, we’ve traveled to some places that are unfamiliar to many (even some geography majors). That's where geotagged photos come in. The answer to the question “Where is Kochkor, Kyrgyzstan?” becomes an experience rather than a one-dimensional text description.
If you leverage GPS technology and online mapping technology like Google or Yahoo Maps, your viewers and readers can interactively answer questions like “Where did you take that photo?” for themselves. When a photo is superimposed on a Google Map, viewers can see both topographical (desert, mountain range, etc.) data and geographical (location) data simultaneously.
Moreover, it’s just plain cool…or, at least we think it is.
The Sony GPS-CS1KA
We wanted something small, light, easy-to-use and affordable, so we opted to purchase the Sony GPS-CS1. It's easily attached to a camera bag strap or belt loop by way of its plastic carabiner. The device takes one AA battery. It is so small and light that we forget we have it most of the time.
To get started, turn on the Sony GPS-CS1KA by pressing the button and holding it until a green light starts blinking. Provided that you have a clear line of sight to the sky (even through a car window), it takes between five and ten minutes to locate a satellite and begin logging coordinates. When the device searches for a satellite, it blinks several times in succession. Once the device finds a signal, coordinates will be logged every 15 seconds thereafter and the indicator will blink steadily once every few seconds.
This device has no interface; it's simply a receiver that logs location data echoed back to it from GPS satellites orbiting the earth. If this explanation causes you pain, think of it as a conversation between GPS device and a GPS satellite:
GPS Device: “Hey, where am I?”
GPS Satellite: “Based on where you are sending your signal from, I'd say you are at these latitude and longitude coordinates”
GPS Device: “Cool. Let me write that down on my little memory chip.”
When the light turns red on the device, it's time for a new battery. If you're outside for most of the day, meaning that the GPS spends its time continually logging coordinates rather than searching for a satellite connection, we have found that a fully charged battery usually lasts eight hours or more. If you spend much of your time out of range of a signal, then the device will consume more power trying to find one.
We've occasionally encountered problems getting a satellite signal outside due to heavy smog or buildings blocking its line of sight (Beijing, China comes to mind). If you anticipate spending a lot of time in a car or boat, make sure that the device is positioned in a window (the satellite signal can be received through glass) or on the side of a boat (above the water level for obvious reasons). If you don't normally carry a camera bag, attach the GPS device to your belt loop.
The storage capacity of the Sony GPS-CS1KA is 31 MB, or approximately 15 full days worth of logs. If you find yourself on an extended journey, you should either download the log files to your laptop or find an internet cafe where you can copy the files from the device to a CD or – more ideally – to a USB thumb drive.
So, if you ever happen to meet us on the road and notice a blinking green light attached to us, don't be concerned. We're not bugged or being tracked (at least, not that we're aware of); it's just our GPS device doing its job.