Monday, May 19, 2008

Geo Tagging

I have a lot of photos most of which have time stamps. But it is more useful to have a 'geo-stamp' , that is, a location stamp for the photo. Most cameras (atleast until now) do not have GPS chips. But there is a very simple automated method to get geo stamps.

All that you need is any camera and a very simple GPS unit (need not have any fancy map or anything).

Set the time on camera:
Before you go and shoot pictures make sure that you set the time of your camera very accurately (to within seconds). Setting the time on the camera accurately is the key for geo-tagging this way. Time is the only common parameter for the photos taken and the GPS track logs. So if the time is off then the lattitude and longitude will also be off based on how fast you were moving at the time of taking the picture.

GPS Receiver track log:
Switch on your GPS receiver and start recording your track. Most GPS units automatically record in either GPX or NMEA formats. Either is fine.
Take as many pictures you want but be sure to carry the GPS along with you (in your pocket or bag at all the times).

After you have taken all the pictures, you now need to use a software called gPicSync (a free open source software which can be downloaded here:

Step by step:

  • Download and install the gPicSync.
  • Open gPicSync.

  • Select the folder in which your photos are located.
  • Select the the folder in which the GPS track is located.
  • Set the time offset: You would have set the time on the camera to local time. But the GPS records all the time in UTC (GMT). So the program would have to know what is the difference between your time and UTC. For San Francisco it is -7 (when day light saving time is on). For India it would be +5.5.

  • Then click on synchronize button.

  • Voila! you are all done ! All your pictures now have a the latitude and longitude information in the EXIF data. If you upload them to picasaweb or flickr, they can be shown on a map with no effort at all!

1 comment:

Danilo said...

GpicSync ? There is a better solution !
I tried Geosetter 3.0.14 (
It is far better respect other like GpicSync. Its GUI interface is well done and has a lot of features.
Simply to use, almost nothing to do to configurate it. In a snap all the photo are geotagged using the data from logger unit.
In a word: wonderful freeware !
Danilo - Italy