Geotagging Your Photos

June 30, 2010 by Darren
Filed under: Blog 

After reading a tweet by LondonBackPacker this morning I was reminded that I had promised to tell you how I geotagged my 2009 TGO Challenge Photos.

There is a manual way using inbuilt tagging functionality of software like Picasa or iPhoto. Which is ok for the odd photo, and assuming you can remember the exact location you took the photo.

But when you have loads of photos to tag is it possible to automate the tagging process? Yes if you have done the following step, otherwise it’s the manual option only I’m afraid.

That step is to record your route using your GPS. On the Challenge each morning I set my Satmap recording my days walking. Then when I reached my camp spot I would stop the Satmap recording, and save the resulting track. So at the end of the Challenge I had 13 days or so of track logs recording my actual route taken.

I then transferred the resulting gpx files over to my pc. These gpx files can be read back into mapping software on your pc, read into Google Earth or Google Maps, or as we are about to discuss used by some free software to tag your photos with the appropriate GPS position of that photo.

Next you need to download and install on your pc a little piece of software that will read your gpx file and match that data against the photos you have taken, and then tag the photos with the GPS co-ordinates of where the photo was taken.

For this I used Photomapper. Photomapper is easy to use, at the basic level you load in your gpx file, point it to the photos you want to tag and away it goes.

One problem I had was that Photomapper didn’t like the gpx files that my Satmap Active 10 generated. So I ran them through GPSBabel, which did turn them into a gpx file that Photomapper liked. (A little aside I believe Mapyx licensed GPSBabel for use in the Quo software to do the data import and export.)

Once I had solved that little problem, I needed to adjust for the clock differences between my Satmap and my camera. Out of laziness my camera clock was an hour out from the Satmap.

And it is important that any difference between the two clocks is catered for. This is because Photomapper (and other similar software) work by looking at the timestamp of the photo, and then finds within the gpx file the matching timestamp (or closest to it) and uses the matching long/lat co-ordinates to tag that photo.

Photomapper then updates the EXIF header (don’t worry if it sounds technical it is just a part of the image where some information about it is stored, such as camera model used,exposure etc) of the photo with the GPS info from the gpx file.

Hey presto we now have our photos tagged with the GPS data, and they can now be loaded in to Flickr/Picasa etc and when viewed you can also see where the photo was taken on a map. Of course the next step is to produce a Google Map with the photos on but that’s another post for another day.

Of course this is all unnecessary if your camera has an inbuilt GPS or GPS attachment. It can then tag the photos with the location when they are taken. But those cameras are more expensive and usually have a poorer battery.

Software Mentioned/Used

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Comments

4 Comments on Geotagging Your Photos

  1. ukmase on Wed, 30th Jun 2010 10:51 pm

    2. Another great post….you really do like to play with new tech. My iphone4 is on order, things like this make it a great bit of kit.

    I would be worried about the ihpones battery going if i had to aquire a gps point each time i took a photo or am i being silly ?

  2. Darren on Thu, 1st Jul 2010 11:22 am

    3. I’ve not noticed it using up the battery that much. It is not noticeable that it is getting the position. I’m not sure when it acquires the position for the photo,or if it is constantly updating in the background. I’ll have to look into it, see if there is anything in the dev kit.
    In the photo viewer now in iOS4 there is a places tab, which will show you where you photos were taken on your iphone (assuming you have switched on location services and are tagging your photos that is).

  3. DaylightGambler on Thu, 1st Jul 2010 3:39 pm

    4. Great post – I had always wondered whether there was an easy way to do this in bulk.

    Timestamps work really well – it is what I use for Social Hiking (http://www.socialhiking.org.uk/map/offasdyke4ms/offas-dyke-4-ms) to add photos and tweets onto a route (added with Viewranger Buddy Beacon the map can update live as you walk)

  4. Lonewalker on Tue, 20th Jul 2010 8:17 am

    5. Thanks Darren, been looking for something like PhotoMapper for ages, the simplicity is stunning – great find!

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