Atomic Clocks, Street Views, and Flash Disks

A few random things caught my eye today:

GPS has brought atomic precision time to us in the form of small portable GPS devices, as well as network time-servers that sync with the GPS data. The time from the GPS satellites comes to us with such precision, because the satellites carry cesium atomic clocks on board and are synchronized with ground-based clocks and being corrected for relativistic effects.
But for some folks getting the atomic time from GPS is not enough - they call themselves "Time Nuts" and have atomic clocks (such as the 5071A) at home as a hobby. See also this nice article in Wired today. Wow! I've always loved time, clocks, calendar calculations, leap seconds, and physics. I guess that's a hobby that I could get into, too....

From atomic clocks and GPS it is only a small leap to navigation, which brings us to cartography, which brings us to Google Maps - and the second item of interest today: Google has launched Street View in eight new cities in the US, including Boston. Very cool.

Last, but not least, here is something I want in my next laptop: Toshiba announced a 128GB Flash HDD yesterday. My current laptop has a 80GB conventional disk drive, and it looks like the form factor of that Toshiba drive would allow for an actual replacement.

Geo-coding your photos efficiently

I love to take photos and digital cameras have certainly become the norm since the turn of the century. A new gadget from Sony recently caught my attention, because it promises to provide geo-coded Lat and Lon information for digital photos through GPS logging.

It is called the GPS-CS1KA and works on a surprisingly straight-forward principle: you turn the device on as you are taking pictures and it simply records your GPS position every minute or so. It is powered by just one AA battery and can record up to 10 hours of position data on one charge. The device comes with a USB-cable and associated software that lets you transfer the GPS logs to your computer. Then, when you have downloaded your photos from your digital camera into your computer, the software will automatically match the GPS log to the digital photos based on the timestamp information in will add Lat and Lon data to the JPEG files. This is appended to the file as regular EXIF information in the same way that your camera uses to store its metadata (shutter speed, aperture, etc.).

And why does this XML aficionado care about EXIF data? Well, that is really quite simple: the well-known jhead utility allow you to extract EXIF data from JPEG images to automate the process of building and manipulating image collections, and a very popular patch for jhead does, of course, support XML output, which makes this ideal for creating galleries/archives/directories or doing any other kind of post-processing for Web 2.0 apps.

I recently tested the Sony GPS-CS1KA device during an afternoon sail in Nahant Bay on a friend's boat, and the operation was indeed very simple. Once I had merged the photos with the GPS information, I uploaded the photos to my photo sharing website, which provides direct linking with Google Maps to utilize the included position data. You can see the result by going to this photo gallery and then clicking on “show” underneath the word timeline and zooming out a bit – this will show our approximate track that day and each green marker represents one photo, which you can view by clicking on the marker.