Some friends have recently expressed interest in knowing how I geo tag my photos, and so this article describes the process.
When I travel, and plan to take photos, I carry either of two GPS devices—a Garmin GPSmap 60Cx or a Garmin Forerunner 305 wristwatch.
* While traveling around, I leave them running, and collecting track data samples.
* When I return home, I connect my digital camera’s SD card to my Mac (using a USB card reader), and copy the image files (of the photos taken) to a folder on my Desktop. (You *could* geo tag the images directly on the SD card; however, in my experience, I’ve found this to be a bit unstable. Sometimes, perhaps due to data marshaling conflicts with other connected USB devices, the Finder will report, “Device Unexpectedly Dismounted”. When this happens, I’ve had my image data corrupted. So, better to just stick with copying them to your hard drive, and geo-tagging them there.)
* I also connect my GPS device (via USB) to the Mac, and turn it on.
* I use [HoudahGeo](http://www.houdah.com/houdahGeo/) to open the folder of images, and geo tag them via GPS device. It does this by reading the current track file off the connected GPS device, comparing the track data timestamps to the timestamps recorded in the image EXIF data, and figuring out where each picture was taken. (HoudahGeo can also tag images selectively using an integrated map browser. This is handy for times when, for example, my GPS device battery died. Since *some* of the images get geo-tagged from the GPS device data, I can quickly tag the others with the HoudahGeo map, since HoudahGeo seems smart enough to choose as a starting point the coordinates of one of the tagged images.)
* I then have HoudahGeo write the GPS coordinates (geo tag) back to the image files as additional EXIF data.
* I then import the images into Aperture (as usual)
* When I upload to Flickr from Aperture, Flickr automatically detects and recognizes the EXIF GPS data (you have to enable this in Flickr’s Privacy Settings).
* At this point, you’ll have a nice map access to your Flickr photos, [like this](http://flickr.com/photos/matthenderson/map).