In the past year, I've done several travel columns. I have had the great pleasure of visiting several places that I thought were of general interest and I shared them with you. I'm toying with the idea of doing another about that greatest of all tourist destinations - Kalamazoo, Michigan (a very cool place, actually), but what I'm going to write about this time is how I used my camera in conjunction with my GPS to easily reconstruct my movements on the New Orleans trip.
Some people have a great memory and some people have a great sense of location. While I'm not bad on either count, I would say that my skills in both of these areas are not great. I could make up for this by taking notes, but I don't do that either. I do own a couple of digital cameras and I'm not shy about using them. While I don't take a camera everywhere I go, I've found that often I wish I had taken it when I didn't think it would be needed. I have the same feelings about the GPS.
If you own a GPS and you read the manual, you probably know that most models keep a track log of everywhere you go while it is turned on. A GPS unit has a limited track memory, but modern GPS units can hold thousands of points - mine holds 10,000. My unit typically takes about five points a minute, but this can vary depending on several things, like how fast and how much you're moving. Typical of modern GPS units, it scrolls off the oldest points once the track point limit is reached - a quite useful default.
If you didn't know about track logs, here's something else that you might find interesting. GPS units time-stamp the track log. Since the GPS unit must know the time precisely in order to calculate its position with respect to several satellites, that timestamp is guaranteed to be right (ignoring time zones, of course).
So why is this so cool? My camera has a clock, too and it time-stamps my photos. Camera clocks aren't so trouble-free: they must be set and maintained by the camera user. I generally keep it set accurately, but it can drift a bit and if the battery runs down, all bets are off. If the camera clock is close to the actual time, then by matching the time stamp of the photo with the GPS log, I can determine precisely where the picture was taken. If the camera clock is off a bit, I can drop the coordinates from the track log into Google Maps, Google Earth or my GPS software and search a bit to refine the fix. In many cities, you can use Google Street View to absolutely confirm the location. At that point, you can find street names and addresses, surrounding roads and terrain, and can even pull up topographic maps and nearby street-level pictures. I did this quite a bit for the New Orleans trip.
Sadly, I didn't have this capability for our trip to England, since I didn't take the GPS with us. I didn't think it would be much use there, but I was mistaken. It's true that we didn't have detailed maps for Great Britain and I wasn't too interested in spending somewhere around $100 to acquire them. We weren't planning to navigate ourselves, I thought, so why bother. But the GPS still works overseas, even if the default maps on the device are very crude or even non-existent. Track logging would have worked and would have been great on a couple photos where I didn't know exactly where we were when I took them. Besides losing out on track logging, we actually did need to navigate some. We weren't driving, but we were walking a lot and we did get lost a time or two. Not seriously lost, but we weren't quite sure how far we were from home base a few times, and once in Falmouth, we had an imperfect idea of where we needed to go to get back to our friends' home. If we had taken the GPS, a waypoint set on our arrival at each place we stayed would have helped greatly - better than breadcrumbs.
The act of assigning location information to a picture (or to anything else) is called geotagging. Many GPS-oriented software products, such as ExpertGPS ( www.expertgps.com) can match track logs with pictures and enter location information directly into each picture. Did you know that you can store a number of important types of information in a digital photo? If you consider a picture as data, then data about that data, known as metadata in the vernacular, can be imbedded in each picture, either as it is taken, or after the fact. The camera generally includes some metadata in each photo, like the time stamp and some info about camera settings and conditions, and you can often include a user-defined string, such as a copyright notice, automatically. There are many more fields in the closest thing existing to a camera metadata standard - Exif (Exchangeable Image File Format). Exif metadata fields can be added to both the TIFF and JPEG image formats, but not GIF or PNG formats. Location information is one of the things you can add and a GPS will help you do it.
Now all of this fiddling can be fun for a few photos, but if you travel a lot, take a lot of pictures, and don't want to do it manually, there are other ways to add location information to your photos. I mentioned software to automatically mate picture data with track logs, but a camera that also functions as a GPS unit makes it even easier. I have heard that digital cameras are available that have GPS built-in. You can also add accessories to do the same thing - Nikon offers a GPS add-on for its newer SLR cameras. If the device is installed and on, and if you can see the appropriate number of GPS satellites to get a bearing, the location automatically becomes part of the picture's metadata.
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Catbar - Brain Candy #139 - Finding Your Way / Brian Rock / Thu Aug 06 21:21:15 EDT 2009
