Monday, October 12, 2009

Fun With GPS

I love maps. Maps of all types. Historical, political, nautical, fantasy (my favorite is Middle Earth), and especially topographical. And when you mix maps with an portable electronic gadget you have a recipe for fun.

Tom thinks I am crazy for wanting to document every location of every picture I ever take. But I like recording this sort of info especially when we are in the wilderness or traveling. For the longest time I was geotagging manually. This is the process of using a program like Google Earth to point to the spot where you know (or guess) the picture was taken, and then the software records the latitude and longitude coordinates on the exif metadata tags.

Don't get me wrong. Google Earth is great, but the process of geotagging is slow. There are more simple programs out there, but I was still running into the problem of not knowing or remembering the exact location of the photo. And after a ten-day trip, this can be impossible.

That's when I started looking into real-time geotagging devices for my camera. But they are expensive and camera specific (and I would probably need to upgrade my camera). For the same price range you can get a unit with topo maps, bells, and whistles too.

The trick for me was to find out how to use the gps unit to automatically geotag my pictures. Automatic is the key, considering I take about 1000 exposures on a 1-week trip. It took quite a bit of hunting around on the internet and experimenting with my unit before I came up with the solution.

The key to automatically geotagging your photos is simple - time and date stamp. Every camera records the time and date taken, according to what you set of course. It is stored in the metadata tags, an invisible universal packet of info that comes with each photo.

So I knew that all I needed was a gps unit that could record my movement in a file with date, time, and location, and the ability to download the data at the end of the trip. In the gps world, this is called a track, and the universal file format is gpx. It turns out that almost all modern gps units will do this.

From Rocky-Brown Mountain Hike SNP

The next step was to find software (preferable free) to read the gpx track file, interpolate where necessary, and write the metadata tags automatically. Surprisingly, Microsoft Pro Photo Tools easily does just that. It will also allow you to change the time/date stamp if your camera was accidentally set wrong. To make things easy, you just make sure the gps and camera are set to approximately the same time.

From Rocky-Brown Mountain Hike SNP

I purchased a simple Garmin etrex Venture HC. It will save 10,000 track points, and a typical hike takes about 2,000 (you can change the resolution setting). I wish I had spent a little more money (well an extra $100) on a unit that has an optional removable SD memory card (my unit has only 24k) so I could go longer without downloading (I don't typically travel with my laptop). I also got the US Topo Maps.

I plan to track every minute of my trip to New Zealand. Matt said I could use his laptop to download data when needed. I don't have New Zealand maps yet, but I found a NZ Road Map opensource project that looks promising.

1 comment:

  1. heh heh - middle earth. so there's nine of us, and i'm the youngest, which I guess makes me Pippin (and Jere' Gandalf - ha!). We could be all dorky and have NZ code names.

    yes, I was sick yesterday - battled some kind of flu thing all weekend, on and off.