I’ve finally gotten a GPS unit, and getting it to play nice with my iMac has been an education. The unit is a Garmin eTrex Vista Cx, which is being phased out in favor of the Vista HCX, which is supposed to work much better in deep tree cover.

All GPS units do the same thing: pick up signals from satellites. All work pretty much the same in recording a track of everywhere you go. The trick for dirt-walkers of our ilk is getting the track out of the unit and pasted onto some kind of electronic map so you can show everybody else where you hiked. The Vista Cx has a USB cable that connects to a chip on the unit; it contains files with .gpx extensions that contain tracks, routes and waypoints. Plug in your unit and launch some GPS connection software, hit the “import” command and voila, your track is on your Mac. (See my technical note at the bottom for more on how this works on Garmin units).

Pretty much any GPS unit with a USB connection should be able to communicate with a Mac (and a PC for that matter, but I’ll stick to what I know here; the concepts are the same regardless of which OS drives your computer). There are commercial Mac-specific GPS programs out there (here’s a list at the site of the makers of GPSy) but I always start out by tracking down the best free stuff.

I have one primary use in mind for my unit: slapping a hiking track onto a Google terrain map for posting here (I’ll get all geocachey someday; Keep in mind it took me four years to try orienteering). Google terrain maps are the closest free thing to having the shaded-relief cartography we usually have to pay for. They depict changing terrain far more graphically (and usefully) than Google Earth images. They are lame substitutes for professionally produced maps — with essential details like identifying trails you didn’t use — but they can be thrown together pretty quickly and e-mailed to your hiking cronies. What I’ve learned so far:

  • EveryTrail.com is very handy. This site allows you to import your GPS tracks and photos from the same site, and can match time stamps to place pictures at key places along the way. It also has easy imports from Flickr. Here’s one I did at Mission Peak yesterday. Here’s the map I created:
  • Horse Heaven Trail to Mission Peak Summit at EveryTrail

    Map created by EveryTrail.

  • GPSvisualizer is a great companion to EveryTrail. You upload your tracks to the site and choose one of a zillion options for making the map just the way you like it. When you’ve got your map done, you can import it directly into EveryTrail.
  • GPS Photo Linker is a handy free app for adding geographic data to your photos. EveryTrail also will do this but I had better luck with Photo Linker. Just drag the photos you want to add to your hike into a window on Photo Linker, and click some buttons to add the data to your pictures. Upload to Flickr and import into EveryTrail and you’re all set.
  • LoadMyTracks can fetch tracks from your GPS or from a GPS file and then it does something cool: offers the option of uploading them directly to GPS Photo Linker, which makes it all that much quicker to build an EveryTrail project.
  • RoadTrip from Garmin is an essential free app for Mac users. It lets you import and export tracks, either directly from your GPS unit or from a file. I used it to create the track above, which was imported into Photo Linker and GPS Visualizer.
  • GPS Babel is must-own freeware for everybody — even if you don’t own a GPS unit, you can use it to download other people’s tracks and translate the data into KML files that can be imported into Google Earth for all kinds of fun and games, such as:

    Mission Peak Google Earth map

    Google Earth lets you save your creations as an image that can easily be uploaded into Flickr or other sites.

  • Google Maps allows a GPS layer — you have to create your KML file and upload it somewhere. Instructions here.
  • Technical note for Garmin users: If you plug your unit into your Mac’s USB port, all you have to do is launch Garmin RoadTrip or pretty much any other GPS application to communicate with the GPS unit. There is an option to mount the internal memory chip to the desktop (as a disk called “no name”), but making the chip accessible to the desktop blocks it from talking to most GPS apps. I got ahead of myself in reading the instructions and thought I had to mount the chip to the desktop to communicate with my eTrex — but doing so interrupted most up/downloads (it would download tracks via RoadTrip, but no routes or waypoints, and wouldn’t connect at all with the other apps). The unit’s much smarter than I expected it to be.

Those are the basics. Share any additions or insights in the comments.