Yes! You Can Use Your GPS with Your Mac!
Date: Nov 18, 2005
One of the drawbacks of being among the Mac faithful—the only drawback, as far as I'm concerned—is the apparent lack of limited-interest software available for Mac users. If you've been using a Mac for more than a short time, you know what I'm talking about. It appears that most profit-motivated software developers would rather produce software for the bigger share of the market—the Windows PC users—than for Mac users. The result: They get software that we don't.
I've been using a global positioning satellite (GPS) navigation for at least eight years now and, until recently, I've had to depend on my lone PC to communicate with my GPS. That means I had to start it up, fiddle around with COMM port cables, and run Windows software (yuck!) to exchange waypoints and track logs and routes between the two devices. I wasn't very happy about that. After all, we all know how I feel about Windows PCs.
One day, I snapped. It wasn't fair, I told myself. There has to be some Mac-compatible software that will work with my GPS. So I went surfing and came away with some great information and a few good pieces of software. Here's what I learned.
A Little About GPSes
Before I tell you about connecting your GPS with a Mac, let me take a moment to tell you a little bit about GPSes. I'll preface this discussion by admitting that I'm no expert. I only know through my experience with the models I've owned and pre-purchase research I've conducted.
I have two GPSes. My Garmin GPS Map 12 is an ancient thing (at least five years old) with a black-and-white screen and only 1MB of memory for storing maps. It works great, but I decided I wanted something a little better when I got into geocaching. So I picked up a Garmin GPSMAP 60C. This little baby has a color monitor and can hold more than 55MB of map information. It's also WAAS-capable, so under the right conditions it can be very precise.
Magellan and Lowrance are two other GPS makers. Although I've never owned units made by either company, they're highly regarded, quality units with plenty of features. And, like most Garmin units, most Magellan or Lowrance units are capable of exchanging information with a computer.
If you haven't purchased a GPS yet, consider computer connectivity when researching options. Although I've never seen a GPS datasheet admit connectivity to Macintosh computers, if it connects to a Windows PC, you may get good results when following the instructions in this article to connect to a Mac.
Oh, and if you know next to nothing about GPSes, take a break right now and point your web browser at the HowStuffWorks page on GPS receivers to learn the basics (and more) about how GPSes work.
About the Data
Generally speaking, four kinds of information can pass between a GPS and a computer:
- Waypoints are individual locations, normally indicated by latitude and longitude. These can be points already programmed in the GPS, such as cities or point of interest; or points that you add, which are called user waypoints.
- Tracks or track logs are collections of points that, when joined together with a line, make up a path. Tracks can be created automatically by the GPS as you move from place to place with the GPS turned on.
- Routes are collections of waypoints for going from one place to another via specific locations. Routes are normally programmed into the GPS to indicate how you want to get from one place to another.
- Maps consist of specially formatted data to display map information such as roads, topographic lines, and cities on a GPS.
Although basic maps are built into GPS models with moving map features, some GPSes also support the upload of supplemental map data from a computer to the GPS. For example, I use my GPSes for off-road travel and exploration, so I upload topographical maps to the GPS for the areas I want to explore. So, while I'm in those areas, I can see topographic lines (for elevation), unpaved roads and trails, water sources, and other data that normally wouldn't appear in the GPS.
The transfer of map data between GPS and computer is usually one way: from the computer to the GPS. New map data uploaded to the GPS overwrites whatever was uploaded last time. Since the GPS doesn't have any map data that the computer doesn't have, there's no need to transfer map data from the GPS to the computer.
The transfer of map data is where things are tough for Mac users: There's no Macintosh GPS map software that supports the upload of map data from a Macintosh to a GPS. So, for example, to get that map data onto my GPS, I have to fire up my PC, pop in a Garmin disc, and use the Garmin software to upload the maps I want. (Of course, if you have Virtual PC for Mac and can run Windows on your Mac, you're all set. And you won't need this article, either.)
But Mac users can transfer waypoints, tracks, and routes between a GPS and a Macintosh. That's what this article covers.
The Hardware Connection
Before you can even consider connecting your GPS to your Mac, you must have the hardware capable of making the physical connection. I'm talking about cables and, in some cases, cable adapters.
GPSes like these support one (or both) of two types of cables: serial and USB. If yours has a serial cable, I'm willing to bet that the end that doesn't plug into the GPS won't fit into any port on any Mac. It's a PC-style, DB-9 serial plug—the kind that fits into a PC's COMM port.
So that's the first challenge: getting the wire that goes from one device to the other.
For my older Garmin, which just has the serial port, I purchased a serial-to-USB adapter. I bought a Keyspan High Speed USB Serial Adapter (see Figure 1). But I'm sure that's not the only one that'll do the job. You can find comparable products by IOGEAR, CoolGear, CableMAX, and USBGear.
Figure 1 Keyspan is just one of several makers of USB serial adapters.
If you have one of these adapters, here's how to use it. Take the cable that came with the GPS and plug one end into your GPS and the other end into the adapter. (It'll be pretty obvious which end goes where.) Then plug the USB end of the adapter into a USB port on your Mac. For best results, use one on the Mac itself, not on the keyboard, or on a powered USB hub.
Keep in mind that you may have to install driver software to use the adapter you purchased. Read the instructions that came with the device.
If your GPS supports USB and came with a USB cable, you probably won't need an adapter. I say probably because not all USB connections work with all software, as I discovered. In fact, even though my Garmin GPSMAP 60C supports both USB and serial connections, I couldn't use the USB cable that came with it to connect to my Mac. I still had to go the adapter route. I hope that this situation will change as more Mac GPS software is developed, and hardworking shareware authors are properly compensated for their work.
Some Software To Get You Started
Sadly, a hardware connection isn't enough to make things work. You still need software. Software is what gets the two devices—your GPS and your Mac—talking to each other.
I experimented with a number of shareware and freeware GPS software products and found three that do what I need to do. Here's a quick look at each of them.
MacGPSBabel
MacGPSBabel is a freeware program written by Robert Lipe and available at SourceForge.net, a programmers' cooperative. MacGPSBabel, which supports Garmin and Magellan GPSes, reads, writes, and manipulates GPS waypoints in a wide variety of formats. I think of it as my "Swiss Army Knife" for GPS/Mac communications. I use it for transferring raw data between my GPS and Macintosh or for converting GPS data from one format to another.
Launching MacGPSBabel displays its main window, which offers several basic but powerful options, as shown in Figure 2.
Figure 2 MacGPSBabel's main window, all set up to download tracks from my GPS.
From this point, follow these steps:
- Start by choosing an option from the Operating Mode menu: Waypoints, Tracks,
or Routes. Then tell the software what the input (source) data is and what the
output (destination) data is.
For example, suppose you want to download saved GPS tracks from your GPS to your Mac. Choose Tracks from the Operating Mode pop-up menu. Turn on the "Use GPS receiver for input" option. Then choose a file format from the bottom pop-up menu. (You can see all these features in Figure 2.)
- Click Download. In the Select GPS dialog box (see Figure 3), use the pop-up menus to select your GPS and specify the port to which the GPS is connected. Then click Continue.
- Use the resulting Save Output As dialog box (see
Figure 4) to enter a name
and choose a location on disk to save the file; then click Save.
Figure 3 Use this dialog box to tell MacGPSBabel about your GPS and your connection.
Figure 4 Use a standard Save dialog box to enter a name and location for the GPS data.
- Now wait while MacGPSBabel connects to the GPS and downloads the data. A spinning cursor appears in its main window while it works; you'll know it's done when a dialog box tells you so. Click OK.
Here's another example. Suppose you just downloaded a list of geocache waypoints from Geocaching.com, which uses a .loc format. To put those waypoints on your GPS, follow these steps:
- Choose Waypoints from the Operating Mode menu.
- Choose Geocaching.com .loc from the middle pop-up menu.
- Click the Select a File button and use the resulting Choose a File dialog box to locate, select, and choose the .loc file you want to import.
- Turn on the "Use GPS receiver for output" option. Click
Upload.
Figure 5 You can also upload data from a file on disk to your GPS.
- The Select GPS dialog box (refer to Figure 3) appears. Choose your GPS model and connection port from the pop-up menus, and click Continue. Then wait while MacGPSBabel does its thing. Couldn't be much easier than that, huh?
These are just two examples of how you can use MacGPSBabel. The more you work with your GPS and GPS data files, the more work you'll find for this great program.
And remember one thing: Just because this software is free, it doesn't mean that the author or SourceForge.net wouldn't appreciate a donation from satisfied users. If you like this software, prove it by sending a few bucks their way. You can learn how when you download the software.
GPS Connect
Chimoosoft's GPS Connect is a freeware program that enables you to connect to a Garmin GPS to display its real-time data on your Macintosh. You might find this feature helpful when working with a laptop. But the feature I like best is the ability to open and edit waypoint data files (on disk or downloaded from the GPS) and upload changed data to your GPS.
Launching GPS Connect displays a disclaimer telling you that the software is in beta. (I use version 0.2 with Mac OS X 10.4 Tiger.) Click the Close button to dismiss the window. Then, in the GPS Connect main window, choose the appropriate port and protocol from the pop-up menus and click Connect. GPS Connect connects to your GPS and displays some information from it, as shown in Figure 6.
Figure 6 GPS Connect's main window after connecting with a Garmin GPS.
To enable real-time tracking, choose GPS Action > Enable PVT Mode. If your GPS has a signal, it displays location data in the window. This information changes automatically as your GPS moves.
To download waypoints from your GPS, click the Download Waypoints button. In a flash, the waypoints are downloaded and appear in a window like the one in Figure 7. What's cool about this list is that you can double-click any entry in it to change its contents. You can also use menu commands to add more waypoints, upload a selected waypoint to your GPS, or save the list to disk for other uses.
Figure 7 A downloaded waypoint list. This one includes all the Geocaching.com waypoints I uploaded with MacGPSBabel in Figure 5.
Terrabrowser
I saved the best for last. Terrabrowser is a Chimoosoft shareware program that not only downloads data from your GPS, but displays it on aerial photographs or maps. All you need is an Internet connection.
The first time you launch Terrabrowser, it displays a warning. Read it and click OK. Next, you'll see a typical shareware nag screen. Wait until 10 seconds have ticked away and click Okay. (If you continue to use Terrabrowser, I think you'll find it well worth the $15 shareware fee, so pay up and enter your registration code.) Finally, you'll see a blank Terrabrowser browser window.
To set up communication between your computer and GPS, choose the correct serial port from the Serial Port submenu under the GPS menu (see Figure 8). Then, if necessary, choose the correct Garmin from the Protocol submenu under the GPS.
Figure 8 Use the Serial Port submenu to choose the correct connection.
Although Terrabrowser should support live tracking, the version I was using (1.5b3) was unable to do so with my Garmin GPSMAP 60C. That's okay, though. I use Terrabrowser for its ability to visually display GPS track logs or waypoints.
For example, suppose you have a specific waypoint saved on your GPS, and you want to see it on a satellite photo. Choose GPS > Connect to connect your GPS. Then choose GPS > Download Waypoints to download all waypoints on your GPS to Terrabrowser. They'll appear in a window like the one in Figure 9.
Figure 9 Downloaded waypoints appear in a window like this one.
Select the waypoint you want to see in a photo and click the Play button in the window's toolbar. (It looks like a blue triangle.) Switch to the browser window. If necessary, choose Photo from the pop-up menu and set the slider to choose a magnification. When the image is finished loading, it will indicate the waypoint in a photo (see Figure 10).
Figure 10 Here's my house (still under construction when this photo was taken in 1997) from a satellite. When I say I live at the edge of nowhere, I'm not kidding!
You can have a lot of fun playing with this feature. Use the slider to change magnification. Use the pop-up menu to change the type of image. Figure 11 shows another example.
Figure 11 Here's my house on a topographical map.
Of course, you can also just enter coordinates in the browser window and click the Play button to view them. Or open a GPX format file that you downloaded with MacGPSBabel or GPS Connect and display waypoints from that. Or do my favorite thing: Download and display an entire track. Figure 12 shows part of a long road trip I made this past summer (when I was supposed to be writing this article).
Figure 12 Terrabrowser can also show tracks on maps or satellite photos.
Try It For Yourself!
This gives you an idea of how you can use three different Macintosh software programs to exchange information with your GPS. And I've only touched the tip of the iceberg (so to speak) on each of them. As you experiment with the ones you like best, you'll find all kinds of cool and useful things to do with them.
Maria Langer is a freelance writer and helicopter pilot who has been writing about Mac OS since 1989. She's always looking for new tricks to teach her Macintosh computers and new toys that will work with them. Maria is the author of Peachpit's bestselling book on Mac OS X, Mac OS X 10.4 Tiger: Visual QuickStart Guide. You can visit her on the web at http://www.marialanger.com or listen to podcasts of articles like this one at http://www.marialanger.com/mariaspeaks.