Techniques for Automatically Geonavigating Photos

Advances in digital photography and geonavigation have provided new capabilities within reach of the consumer to capture latitude, longitude, and compass bearing along with digital photos. Relatively inexpensive Global Position System (GPS) units, like the GARMIN Gecko 301, can provide accurate latitude and longitude along with compass bearing to a reasonable accuracy (2 degrees). The digital compass can be mounted on the hot shoe of the camera to capture compass bearing relative to the camera line of site when a photo is taken. Two ways of storing this information are evaluated in this analysis. A camera-independent solution called the Jelbert Geotagger (http://www.geotagger.co.uk/) provides a hot-shoe mount and data logger to record the National Marine Electronics Association (NMEA) data stream from the GPS/compass as the camera's hot shoe signals the logger to store an entry on a Secure Digital (SD) card each time a photo is taken. The observations can be time matched and written into the photo's Exchangeable Image File Format (EXIF) header using commercially available software. Another solution called the Redhen DX-GPS (http://www.redhensystems.com/products/video_collection_hardware/default.asp?sm=1) provides a hot shoe mount and cable to write the latitude, longitude, and GPS data in real time directly to the EXIF header of the photo in certain camera models, such as the Nikon D300, D1X, and D2X. Once geonavigated, the photos contain a permanent record of location and time, and they can easily be displayed on maps in applications like Google Earth. Geonavigated photos can be particularly useful for severe weather verification, damage surveys, and research projects involving storm observations. This study will provide examples of geonavigated storm observations from the Spring of 2008. It will also provide some discussion of the strength and limitations of the new techniques and how they could be used to complement more advanced solutions in the Verifications of the Origins of Tornadoes Experiment 2 (VORTEX2).