Keys Corner

I bought an i-Blue 747 GPS track logger recently. You can pick one up, new, on eBay for around 40 – 50 Euro. The idea is to use it to tag photos with their position – our cameras don’t have GPS receivers built in, and often when we get back from holiday, its difficult to remember where exactly we took which pictures. If you set the clock in the (digital) camera before you set off, the time-stamp from the GPS log, together with the position data allow you add the exact position of each photo to the EXIF data that the camera stores when each picture is taken.

The problem is, few GPS loggers come with any software for downloading and processing the track data on a Mac. I’m not aware of any that supports OS X “out of the box”. However, there is lots of third party software around which can be used to read out the scans and process them on the Mac. It takes time to track them down, however. So here’s what works for me:

1. Installing the USB Driver
   The i-Blue 747 uses a CP210x USB bridge chip. A suitable driver allowing the logger to be accessed via a USB port is the Silicon Labs Intel Mac USB Driver, which you can get here (Silicon Labs Intel Mac USB Driver). (I wasn’t able to get the driver from Silicon Labs own web site, which has a different size, to work.)


2. Getting the logger to talk to the software
   One small problem if you have a Mac with a slot-loading CD/DVD drive, is that the software and handbooks that come with the GPS logger are on a mini-CD, which the drive can’t load. So you’ll need to find a PC or mac with a tray-loading drive to read the mini-CD and burn a full sized one if you want to read the handbook.

   Even if the handbook only contains the description of how to use the Windows software, there is still an important peice of information included, which I missed initially and which cost me a lot of time thinking that the logger was defective: to access the track logs and to change the settings of logging frequency etc., the device must be powered up. In other words – it won’t talk to the software, any software, unless you have set the switch on the side of the logger to “log”!



3. Reading the tracks from the GPS logger / Setting the logger’s parameters
   The easiest-to-use software that I have found is without a doubt Mountain Rose’s Mac TravelRecorder. It costs $49 / 37 Euro (but there is a one-month demo version which you can use to to check it out before buying). Use the SLAB_USBtoUART port and connect at 115200 Baud:
   

   Typical settings, which worked for me, are:
   
   For me, a logging frequency of 20 – 30 seconds is often enough to produce a reasonable track of where I have been, and to identify where a particular photo was shot, but if you want really accurate tracks, you can increase the frequency to once a second – but then you’ll only be able to store around a days-worth of tracks, instead of a holiday’s worth!

   The tracks, downloaded from the GPS logger look this:
   
   The tracks can be exported from the application into files formatted for use with Google Earth, or several other common formats.

   Here is one of the sets of data from the above screen shot, imported into Google Earth. As you can see, even though I was driving at speeds of up to 100 km/h the resolution is high enough, at once every 20 seconds, to see exactly where I have been:
   



4. Other useful links
   MTK Based GPS datalogger Management SW: I actually first got the logger working using the software described here (Download link for the software). However, it helps if you know your way around the Mac at Unix level, which I don’t, otherwise it is likely to take a bit of time to get the software set up. It has one very useful feature, which I haven’t seen elsewhere – you can change the log format, and the logging frequency without erasing the existing log on the device.

   MyTrack can import tracks in GPX format (and from the logger, although I haven’t got that working at the moment), and display them on maps extracted from Google Maps, showing the elevation profile and speed profile, and also allows geo-tagging of digital photographs using EXIF data fields.

   Other GPS programs for the Mac: Try this link here, click on the Mac tab at the top of the page, and search for GPS.

We are going to be trying out linking the track records to photos on a trip to Spain in the next month, and if I don’t get round to posting about that before we go, I’ll talk about it after we return.

This entry was posted on Saturday, September 13th, 2008 at 10:09:36 and is filed under Apple, Computing, Nature and Science, Photography. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.