Redundant Track Log


Today’s Question: My camera has GPS, so my photos can be tagged with location information automatically. It also has an option for recording a track log. Why would I need both options? Is there any reason I would ever need to record a track log when I already have GPS for my photos?

Tim’s Quick Answer: In my view the only reason you might want to record a track log is when you will be photographing in a situation where the GPS signal might be intermittent, causing some of your captures to have missing or inaccurate location information.

More Detail: In theory, if you enable the GPS feature on a camera that includes a GPS receiver, all of your photos will have location information added to the metadata at the time of capture. In reality, that location information can often be missing or incorrect. Recording a GPS track log can help.

In order to add GPS coordinates to the metadata of a photo at the time of capture, the camera must have a good signal from a set of GPS satellites. If you are indoors, for example, you will generally not have good GPS reception. In the absence of a good GPS signal, the location information in metadata will generally be left blank.

In some cases the camera may temporarily reflect an outdated GPS location. For example, let’s assume the last photo you captured included location information based on a good GPS signal. You then walk indoors through a large shopping mall, exiting at the other end, where you capture another photo. That photo may include location information from the opposite end of the shopping mall, based on the camera retaining the GPS location information from before you went in doors.

Both of these scenarios could be resolved by recording a GPS track log in the camera, even when you have enabled the automatic recording of GPS metadata for your photos. In situations where you know the GPS signal may be intermittent, you can record a track log and then synchronize that log with your photos later in your workflow. That, in turn, would enable you to update the metadata for photos that have missing or inaccurate metadata.