Using a Garmin Foretrex 101 with an Apple MacBook

In my previous post I wrote about the process that led to my purchase of a Garmin Foretrex 101 handheld GPS unit (or wearable personal navigator as it says on the box). This post provides some more detail of how I am using it with an Apple MacBook.

The first problem is how to connect the GPS to the MacBook. It would be nice if the GPS unit had Bluetooth capability so that you could wirelessly transfer data direct to the MacBook. But it doesn't. Instead it has a serial connection - which is absent from every computer I've bought this decade. After some poking around on the Internet I found that there were several serial/USB converter cables available. Garmin list one as an accessory for the Foretrex 101, but it gives a list price of £33.99. Instead I plumped for a cable from Amazon, supplied by iBox Ltd, with postage it came to the grand total of £4.70.

The converter cable arrived after a couple of days - well ahead of the main Amazon order which included the GPS unit itself. The cable itself was slightly different from the one in the photo on the Amazon page, in that although the actual 9-pin serial connector itself was male, it had screws to secure the connection instead of hexagonal sockets. Fortunately I was able to liberate a pair of hexagonal nuts from an old serial extension cable to make sure it stayed firmly connected to the serial plug.

A driver is needed to get the converter cable to work with Mac OS X (I'm running OS X 10.5.7 on my MacBook), and a mini-CD was provided with the cable, although you can't use it in a slot loading drive like the MacBook has. The driver needed for OS X is in /Prolific/PL2303X/MacOS-X/PL2303_1.2.1.dmg. Although I went to the Prolific web site and downloaded the slightly newer 1.2.1r2 driver.

You can check that the converter cable uses the Prolific PL2303X chipset by plugging it in and going to System Profiler and checking Hardware > USB section for a device called USB-Serial Controller. It should have a Vendor ID of 0x067b (Prolific Technology, Inc) and a Product ID of 0x2303. Once the driver is installed and the cable is connected there is a new serial device called usbserial, which shows up as /dev/cu.usbserial and /dev/tty.usbserial.

As I was still waiting for the GPS to arrive I tested that the cable was working by plugging in a serial trackball that I had and running od /dev/tty.usbserial in a Terminal. Output appeared when I moved the trackball or clicked a button, so it was looking promising.

The actual GPS unit itself arrived a couple of days later, along with the serial cable. Although the cable is listed on the Amazon site as "Garmin PC Cable (Forerunner 201 & Foretrex 201)" it works fine with the Foretrex 101 too.

At first I didn't much care for the idea of it being wrist mounted. Some of the reviews I had read online claimed the Foretrex 101 was no bigger than a watch. It is a lot bigger than any watch I've ever had, but it is surprisingly light. With batteries installed it weighs in at just under 100g, whereas my watch weighs 80g. And it does seem to function well on your wrist, and if you really want to know the time (and date) it's there in a tiny font on top of the Main Menu page. Or you can select it as one of the readouts on the useful Trip Computer page. After a couple of experiments of putting it in my pocket I attached the wrist strap and now I always use it on my wrist.

Loading data from the GPS to the MacBook is quite straightforward using a GPS utility such as LoadMyTracks. First you need to plug the 2.5mm plug of the serial cable into the GPS. The port is hidden behind a little weatherproof rubber flap. Make sure the plug is pushed in all the way. Then plug the USB cable into the MacBook, turn the GPS unit on and fire up LoadMyTracks. You should select "Garmin Serial" from the dropdown and "usbserial" as the serial port to use, then make sure the GPS unit is turned on and click "Acquire". The application will prompt you for a location to save the data in and will show a progress bar as it transfers the data. The GPS unit will beep and display "Transfer Complete" once the process is done. The data can be saved as a KML file to use with Google Earth, or a GPX file for a variety of uses. I am currently loading GPX files into TrailRunner to keep a log of my GPS tracks.

The GPX data can also be used for geotagging photos using a utility such as GPSPhotoLinker. The best way I have found to geotag photos for use with Apple iPhoto '08 is do this is as follows:

• Synchronise the clock of your digital camera with the GPS before you start.

• Take your GPS with you when you take photos.

• When you get back - before you load them into iPhoto - first make sure the clock on the camera is still synchronised to the GPS. If it isn't just take a photo of the clock on the GPS screen, and then you can use the time difference when tagging the photos.

• Plug the memory card with the photos on into the Mac, and quit iPhoto (if it starts automatically).

• Use GPSPhotoLinker to geotag the photos on the memory card. You can use the application to timeshift the photos (if you forgot to sync the camera in the first place), and to check the location you are tagging with before you actually tag the photo.

• Unmount the card from Finder to make sure the tags are written out to the media.

• Re-insert the card to the Mac and then import the photos into iPhoto.

Note that with iPhoto '08 you need to geotag the photos before importing them, but once they are imported you should be able to see the location data by bringing up the "Photo Info" window (the GPS data is in the "Exposure" section). You can also select "Show File" to bring up the image file in Finder, open the file with Preview, and then use "Tools > Inspector" to display the GPS data (and then you can click on the "Locate" button to view the location in Google Maps).

For general use the Foretrex should be set to "Garmin" on the Settings > Set Interface > I/O Format page, although you can get it to stream GPS data direct to a Mac utility such as GPSUtility by setting it to "NMEA". (Although I have yet to find a use for this).

(Now) I Know (Where I'm Going) Our Kid

Every few years over the last decade or so I have considered getting a GPS and/or SatNav unit, but after spending a while investigating the options my interest has always petered out. Part of me thinks that a GPS is unnecessary and if you know what you're doing a decent map should suffice. Indeed, I have managed to complete my round of the Munros without recourse to such electronic gadgets.

But that was before Google Earth. Having spent some time trying to remember the exact routes of all my Munro walks and recreate them in Google Earth as KML files I have come round to thinking, not what a useful aid to navigation a GPS would be, but what a lot of time it would save me if I could just dump a GPS track log and generate KML files from that. It would also be a positive boon in geotagging photos. In theory you can simply synchronise your digital camera's clock to the GPS before you set out on a walk (or take a photo of the GPS clock screen and sort out any time differential later) and then use the GPS track log to determine where you were when any particular photo was taken. Certainly beats messing around trying to place photos on your Flickr map after the event.

The path to actually getting a GPS started when I was casually leafing through a flier from Maplin there was a product on it called a GPS Travel Tracker. It was £40 and promised to "record and trace your journey using GPS technology". Caroline suggested I could get one for my upcoming birthday. It was interesting, but didn't appear to have any sort of display. What use is a GPS if it can't actually tell you where you are? I found Maplin were selling a similar model with a display for £70 (Holux GPSport 245), but it looked like it would only give your location as latitude/longitude - which might be quite useful if I was an 18th century mariner, but not so handy for using with my collection of OS maps.

For only £10 more I could get a Garmin eTrex H - the same model that I'd used in Norway to verify our location on our snowshoeing trek. Admittedly it was somewhat larger, but it can report positions on OS and WGS-84 maps, it can also do waypoints and routes, and I can vouch for its operability whilst wearing gloves in a blizzard.

My further investigations on Garmin handheld GPS units revealed that the units I had been looking at 6 years ago (such as the Geko 201) were still available, but now slightly cheaper. The development of the handheld GPS appeared to have followed two distinct paths. Firstly the handheld form factor has been retained, but screens have got bigger, become colour (and touch sensitive in some cases), maps from internal memory or SD cards can be displayed, allowing turn-by-turn navigation functionality like SatNavs. Some of them have even got cameras in. And they can cost several hundred pounds.

Meanwhile the smaller form factor, which started with the Foretrex wrist mounted series, has turned into the Forerunner series, which have finally shrunk down to watch size, and contain all sorts of functionality aimed at avid runners. But after having downloaded and read some of the manuals it wasn't clear that you could actually get a useful map grid reference out of them. So, in spite of their small form factor, they may not be that useful to me after all.

I decided I should get all an all-singing all-dancing handheld that could do everything I might possibly ask of it. I'd be able to use it for navigation on the hill, and as a SatNav in the car.

The next morning I awoke realising that everything I had decided the previous day was rubbish. What I needed was a small, light device that wouldn't be too much hassle to take with me anywhere (so I can use it's data for geotagging photos). It should be waterproof and have a display that can tell me where I am on a map, and I should be able get the data off it and on to my MacBook. That was about it. I decided if I wanted any more I could buy a separate SatNav system, which would have the added advantage that Caroline would be able to use the SatNav to meet me with the car at the end of a walk, while I had the GPS with me.

So, I settled on the Foretrex series, which I first looked at in 2005 and are still available. They are a wrist mounted version of the larger Garmin handheld GPS's and weigh 78g and are waterproof. The choice is between the 101 model (which takes 2 AAA batteries) and the 201 model (which has an internal Li-ion battery and comes with a integrated charger/serial data cable cradle, is a slightly different colour). The 201 is £20 more, but by the time you've added in the cost of a data cable and some batteries to the 101 they are almost the same price.

The major drawback with both units is that they come with a serial interface, which even when it was introduced was clearly a technology that had got a bit long in the tooth. But a bit of Googling led me to believe I could get a serial/USB converter cable for a few quid (or £34 if you buy it direct from Garmin), that would let me connect the device to my MacBook over USB. (This post has got quite long enough, so the serial/USB story will be a different post).

So, I plumped for the 101 as it has replaceable batteries. Although the 201 is a completely sealed unit - and so is probably more waterproof - I have a few qualms about how well the internal Li-ion will cope in a few years as they do deteriorate over time with use. With the 101 I can just bung in new batteries as I need, and if I end up going on a multi-day trek I can carry enough spare batteries to last for the entire time.

I ordered the unit from Amazon (£89), along with a data cable (£11) and a serial/USB converter cable (£5). I shall write up my experiences of using it with my MacBook for logging routes and geotagging photos in a separate post.

Interestingly, as I write this, Garmin seem to have updated the Foretrex line with some new models. The 301 and 401, which seem much the same as the 101/201, except the package is slightly narrower, the units have a more up-to-date GPS receiver, have slightly longer running times on a pair of AAA batteries and sport a USB connection. The 401 model has an electronic compass and a barometric altimeter. They are due to be available in Q3 2009, pricing is to be announced.

Update 2009-07-16: Amazon now has the Foretrex 301 and 401 units available for pre-order (due on the 20th July 2009), priced at £170 and £200 respectively.

Oh, for the uninitiated, the title of the post refers to The Shirehorses spoof of The Seahorses "Love Is The Law". For those that have been missing Mark & Lard since their last Radio 1 show five years ago, there is plenty of their material on YouTube.

Thumping Good Stuff

Macaroni Penguins have become the proud owners of a new PA system. We have just purchased a pair of Tapco Thump TH-15A powered speakers. This means that the rather excellent Mackie SRM350 speakers that we have been using for the past few years can now be repurposed as stage monitors, so that when we play we can now hear what the rest of the band is doing. (For better or for worse).

We took delivery of them on Friday and on Saturday we tried them out when we played the 2009 Dursley Rugby Club Beer Festival, and judging by the audience reaction they could certainly hear what was going on OK. And so could we, so everyone is happy.

One minor drawback though - according to this promotional video, cat owners might want to refrain from bringing their pets to our future gigs.