I decided a while ago that it would be useful to "geotag" my photographs,
i.e. to automatically record the location from which each is taken and add that
to each images's metadata. As my next photographic trip is to Iceland and I rate
my chance of correctly remembering and spelling all the Icelandic names as about
0%, this could be very useful.
I looked at commercial solutions, but they
have several drawbacks, including the need to carry at least one more gadget,
and some questions about how they would fit with my photographic workflow. Then
I realised that I could achieve a similar result using just my new mobile phone
and some low-cost software which can integrate neatly with my Bibble-based
workflow.
The core of the commercial solutions is a small dedicated GPS
receiver which records your "track" over time. However, as most recent
smartphones also incorporate GPS this is something the phone should be able to
do, and true enough there are "apps" for most phone platforms which achieve
this. My HTC is based on Windows Mobile 6.5, and the choice was a bit limited,
but I tracked down a free piece of software called GPSToday from
www.geoterrestrial.com
which does the job fine. I have it set to get a GPS location every 10 mins when
it can get a signal, and this seems to be a reasonable balance between
resolution, file size and battery drain (no more than an extra 5-10% per day).
When out shooting you just need to make sure that your phone and camera are set
to the same time (and time zone if they support it), and that your phone is
exposed enough to get a regular GPS fix. I try and remember to get a manual fix
at the start and end of shooting at each location, but this is probably not
strictly necessary.
When you've finished shooting and downloaded your
images, the next step is to get the tracks into GPX "track" format. (This is a
standard XML format for this type of data.) You may be lucky and your phone/app
support this directly, but if not you'll need to convert your track file(s)
using GPSBabel (
www.gpsbabel.org),
which can convert any GIS data format into any other. This can take a bit of
work to set up, but eventually you'll have files full of <track> elements and
you're good to go.
The actual geotagging is done by the Geotag program (geotag.sourceforge.net).
This is written in Java and doesn't need much installation, but you'll also need
to install and locate
ExifTool (www.sno.phy.queensu.ca/~phil/exiftool)
which does the work of reading and writing the image metadata. It's worth
reviewing the settings and in particular how the location data is saved. You
have the option of writing direct to the image file, but it's probably safer and
in some ways easier to select the "Always write to XMP files" option.
The
first step is to "Add images from directory..." - simply browse to the directory
with your incoming images. If you shoot RAW+JPEG like me you probable want to
just select the RAW files. Next, you select your track file via "Load tracks
from file...". Then you select the images you want to tag, and right click to
first "Find locations - for selected images", then "Location Names - for
selected images" if you want toad textual location information as well as
coordinates. If you need to manually adjust any of the tagging information then
Geotag makes it easy to do so.
The geotagging information is saved automatically. You can then open the
images in Bibble. The act of doing so copies the geotag information to Bibble's
settings, so it is written to Bibble's own XMP. Files, and into any output
files. Once this is done you can get rid of the Geotag XMP files.
All this software (apart from Bibble) is available for a small donation and on most platforms. Have fun!
If you'd like to comment on this article, with ideas, examples, or just to praise it to the skies then I'd love to hear from you.
© Questa Computing Ltd. 2005
Page last updated
14 May, 2015 12:32