By Greg & Helen Sosna

Ever forgot where your pictures were taken? Wanted to tell someone where you were when you took it? Or maybe you just want to find all your pictures in a particular location…

Many web-photo-sharing sites allow you to tag a photo with its location – including Picassa & Flickr. Even with Google Earth doing so is difficult, slow and very manual!

But wait, haven’t you got a GPS? A digital camera? Both of them record a time, and with a bit of luck, you just might be able to match them together! This process is called geotagging or geocoding, and the JPEG file standard already allows for storing GPS information as part of the EXIF extension!

There are many free or cheap programs that let you do just that. I will recommend two free ones towards the end of this article.

Let’s begin with the gear. In the near future, most digital cameras will come equipped with a (hybrid?)-GPS unit and you probably won’t even need to worry about all of this, but the ones that are out now are very expensive & uncommon. So we’re left with your GPSr and a digital camera of your choice.

Most handheld GPSrs record a tracklog, continuously logging the longitude, latitude & date/time while the unit is switched on. Some of them will also record elevation too. You will also need to be able to download the tracklog onto your PC, so you also need a working connection between GPSr and the PC (serial cable, USB, Bluetooth).

The only requirement for the digital camera is that it records the time/date the picture was taken (preferably inside the JPG as EXIF tags), and that the time on the camera is synchronised with the GPS (your GPSr receives very accurate time from the satellites, therefore you only need to set the camera’s time from the GPSr). It’s a very good idea to check/sync the time on the digital camera before each shooting as some cameras lag or run ahead of the time, and an accurate sync is very important. You will learn how good your camera is at this with time. With good software, it is possible to adjust the EXIF times after the fact, or you can even take a picture of the GPS unit with time/date on the LCD to sync later!

Let’s get started! While you’re out:

1. clear the current tracklog, and set the logging resolution to maximum (play with this later for best results)
2. after getting a satellite fix, synchronise the time
3. TAKE PICTURES! – while taking pictures, make sure GPS is on and fixed!

We found that our Geko 201 (similar to E-trex – but please let me know your results!) is able to store 10,000 points, and the memory lasts for about 4 days of daylight wandering and shooting, before it gets full. If you’re using a Garmin GPSr, try not to “save” the tracklogs, as that looses a significant amount of resolution without warning you (and the manuals fail to mention that!) – so just use the current tracklog. Apparently the latest Garmin X-series allow you to record GPX files directly to a microSD card, which avoids that problem and lets you record months of tracklogs!!!

Back home:

1. Download the tracklog from the GPS. You can either use the software that came with the GPS, or download some free software to download the logs. Usually you will need to get it to a GPX format too (look up GPX converters).
2. Download the pictures.
3. Use software to geocode the pictures (see below).
4. Use GPS-EXIF aware software to view the info (IrfanView, Picasa, Flickr, PanoradoFlyer… there are tons of them available, and the support for this functionality will only become better and better!!!)

Software to geocode your pictures:

As I mentioned before, there is a number of freeware and cheap software available that do this. I recommend the following:

·         http://www.grazer.de/ - very basic and simple, but functional

·         http://www.geosetter.de/en/ - more advanced with online maps, adjusting timestamps, and heaps of other great functions

Remember, the software will not change the picture itself, just the EXIF and IPTC tags!

I would be interested to hear what combination of GPSr / Digital Camera you have used, and your experience with this – any further comments or feedback is appreciated, as this is a working article!!!

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