Tuesday, May 18, 2010

Getting Started With A Garmin Forerunner

The Garmin Forerunner GPS-enabled fitness monitors are powerful devices. Their GPS features can be used for land navigation. Many models have a heart rate monitor that can be used to measure the intensity of your workouts. They have robust system configuration menus that let you modify the display fields to suit your individual needs for many types of activities. They have map displays that show your tracklog and waypoints graphically. And you can upload your data to your computer or favorite fitness web site to analyze your performance. Like everything in life there are trade-offs. Powerful systems with many features are hard to master.

I've helped a lot of people learn to us their Garmin Forerunners. There are a few things that I recommend you try as you're getting comfortable with your Forerunner.

1. Learn the basics. See my previous blog post on this subject.


2. Use autolap. Breaking you run into segments allows you to analyze your performance in discrete segments. You don't need to run on a track or go a set distance, you can mark the end of a lap any time by tapping the lap button. It can be very useful to have your Forerunner automatically record a lap at set distances. The auto-lap feature does this for you. It's enabled by default on 310XT. It's disabled by default on a 305. Here's how to enable it.

Power on your 305. Click on mode until you see the menu with "History, Training, Navigation, Settings" menu. Use the down arrow button the the right side to select Training, then press the enter button. Click enter again to select "Training options", then scroll down to select "Auto Lap". Click enter on the first field to select "By Distance" and then use the default of one mile. This will automatically record a lap each mile you run.

2. Use average pace and lap pace on your default display. Instantaneous pace or speed on a GPS is not very useful because the value fluctuates so much. This is because there are always small random errors in the GPS system. The average pace is very accurate because the random errors cancel each other out over time.


Average pace is a great way to see how you're doing relative to your goal for an activity. Say you want to finish a marathon in four hours. You'll need to maintain an average pace of 9:09 per mile. If you have a watch on your wrist you can do the math at each mile marker to see if you're maintaining your pace. The average pace function on your Forerunner does the math for you. By glancing at the average pace display you can tell how well you're doing. You don't need to be at a mile marker and you don't need to do any arithmetic in your head. That's a great reason to have a GPS on your wrist.

Lap pace is also very useful, especially when combined with autolap. By displaying both lap pace and average pace you can not only see how you're doing, you can see how you're doing lately. Late in a marathon the average pace will change slowly if you speed up or slow down. Lap pace tells you how fast you're going in the most recent lap. This tells you how far off of your goal pace you're running since the last lap.

To enable average and lap pace displays select "Settings" from the main menu. Select General and then press the Enter button. Select Data Fields and then hit enter. Select "Main 1" then hit enter. From there select 4 fields and then set the fields to display as "Time", "Average Pace", "Distance", and "Lap Pace".

With this set-up when you head out for a training session or race with a goal in mind, figure out the pace you need to maintain to meet the goal. Your Forerunner will tell you how well you're doing relative to your goal and the lap pace will tell you how you're doing lately (since the most recent autolap every mile).

Sunday, January 3, 2010

Visualizing GPS Tracks with Google Earth


It's fun to share your activities that you record with your GPS. There are a few easy ways to share the data and maps, including the Garmin Connect and RunSaturday web sites, and by saving images from SportTracks and posting them to DailyMile or emailing to your friends. You can make your story even more interesting by using Google Earth to create 3d images that show the terrain and even animated fly-overs of your activities.

The image above is a great example of a 3d image. It shows the GPS track recorded while skiing at Kirkwood superimposed on an image of the ski hill. Notice that the perspective is looking up toward the mountain, not straight down onto a flat map. This makes the image much more dramatic than the flat maps we typically share. Can you imagine skiing down those steep faces?

Making these type of images is simple. You start by recording your activity with your GPS just like you normally would. Turn on your GPS, make sure the satellites lock in, hit the start button, go have fun outdoors, then hit stop when you're finished.

I use SportTracks to track my runs. It's great as a logbook. It also provides some nice features including data smoothing and elevation correction via a plug-in. It's also very easy to export from SportTracks to Google Earth. Here's where the fun begins.

When you export to Google Earth be sure to set split markers. I usually use 1 mile increments. The split markers are important for creating animated fly-overs.


Once you have the activity open in Google Earth you'll want to enable the terrain layer. The layers panel is on the lower left of the Google Earth window. Expand the panel if it's not visible, then scroll down to the Terrain section of the list and click the check-box to enable the terrain.

It's also useful to enable terrain exaggeration. You can find this on the Google Earth Preferences panel. Somewhere between 1.5 and 2.5 works best.

Now you can set your perspective by using the navigation controls in Google Earth. You can move left and right, forward and backward using the arrow keys. The tilt angle is controlled by holding down the shift key and then hitting up and down arrow. You can rotate your view by holding down shift and hitting the left and right arrow keys. Zoom in and out using your mouse scroll wheel or the on-screen zoom controls. Once you get the view you want you can save an image using the File, Save, Save Image menu options.

To create a spectacular animated fly-over you can set the perspective for each of the mile markers SportTracks created when you exported the activity. Highlight the first mile marker on the activity panel, set your view using the navigation controls, then snapshotting the view of the split marker. Do this for each split mark, then play the activity using the play arrow on the left hand side. You can then save the activity as a KMZ file and post it online or email it for your friends to play in google earth.



I created a fly-over of the Ohlone Wilderness 50K Trail Run ultra marathon course. You can download a copy at http://tinyurl.com/ohlone50k Download the .KMZ file, open it in Google Earth, then hit the play button. I think you'll agree that the animated fly-over with perspective and terrain tells a better story than a two dimensional map.