Recently, I went out with my friends and made some pictures outside. I always try to record the geo information if possible, so I used my GPS-Logger. After I shared the GPS track with my friends, I realised that the recording and the extraction steps changed a lot since my last post on it in 2008. Since my friend wanted to know more details, I would like to report about the geo steps in my photo workflow.

The principle of storing geo information is simple. Pictures shot by the camera contain timestamps. A GPS signal receiver gets its time information from the satelite – so to any time of GPS fix, the time information is available. A recording device just samples the GPS coordinates and timestamps. A simple correlation of this two sequences allows to enrich the image data with geo information.

In practice, I’m using a GPS Logger Holux M-1000C for recording. The usage is simple – I just switch it on before my photo session and it starts recording. After I get home I first read out the track from the device using the ezTour software which is a kind of a driver to produce a GPX file. Then, I import the pictures from the camera and store them into an arbitary folder. Finally, using the GPicSync software I write the geo information into the EXIF tags of the RAW-format pictures. For this purpose, the GPX file and the folder with RAW files is selected and the synchronization process is started.

Before further processing in the workflow, it is important to make sure that the metadata information is up-to-date. In Lightroom, I have to explicitly update the metadata, since it is stored in the catalog. I prefer the geo information in IPTC keywords, EXIF and in image description, but you can choose where to put it in. After processing and export to FlickR, the geo-coded pictures can be displayed on the map.

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