Tuesday, August 4, 2009

Motion(X) sickness

I promise that I'll eventually stop complaining about the GPS functionality of the iPhone but this morning's experience made me wonder if the whole concept needs a few more years to develop into a viable technology. I got off to a good start today in terms of timing, I was dressed and ready to make it out the door by 4:00 AM. This was important because that extra ten minutes would give me more time to run and I really wanted to work on distance as I train for my August 23rd race. If I'd ignored the iPhone on my way out I would have been much better off since it added to my setup time and - therefore - took away from my run time. That would have been forgiven if the result was even remotely accurate but the GPS app did not come through. More on that later.

Yesterday, instead of doing my usual elliptical workout, I decided to work on my upper body that I've sorely neglected over the last month. I started with 20 minutes of arms-only elliptical and followed with 15 minutes of free weights. I didn't want to overdo it so I stopped there. I worked up quite a sweat in the process, something I'll attribute in equal parts to hard work and oppressive humidity. Today I was anxious to get back out on the road and after having a carb-rich lunch and small but well balanced dinner I woke up feeling ready. As I mentioned above I started a few minutes early and even with the extra work stuffing the iPhone into the armband I was outside stretching by 4:09 AM. I turned on the MotionX application and was disappointed, but not surprised, to see that the GPS wasn't acquired by the time I was ready to leave. I started off anyway and switched on the app knowing it would start tracking eventually.

I got a little confused along my course because so many of the streets look the same, especially in the pitch dark and saw that I was on a different street than I'd expected. I figured that the MotionX map would show me where I went wrong when I reviewed it post-run. I felt great and could have easily gone on well past my time imposed limit. I ended up covering 2.6 miles at a 9:09 pace. This was good considering that I wasn't really thinking about speed as I ran. The MotionX was completely off with the path showing me running through people's homes and across lawns and through back yards. I thought in the early morning there would be far fewer things that would interfere with the signal. While the Garmin (accurately) showed 2.6 miles traveled, the MotionX showed 2.09 miles. It did show me where I veered off onto a different street so at least it keeps a true, if sloppy, record of my course.

4 comments:

  1. Rebooting your iPhone often resolves GPS signal issues such as this...

    Another thing that helps is resetting Location Warnings from your iPhone settings under General>Reset>Reset Location Warnings.

    This is likely an iPhone issue, not MotionX -- I've often seen similar problems in other navigation apps.

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  2. Thanks - I'll try anything to improve the performance!

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  3. Yes, I have had the same issue. Reboot your iPhone. You may even have a deficient GPS chip (An Apple Store will switch your iPhone... I had to do this twice),

    So I reboot my iPhone and then I wait until the blue Globe. That changes everything. I also understand from MotionX Tech support that they have an upgrade that uses multiple sensors to improve the iPhone GPS accuracy.

    I've been running with MotionX for three moths and can't live without it.

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  4. I did start off with a reboot each time I tried the GPS apps. I think the issue is simply that the margin of accuracy with GPS is as good as it gets. It works by triangulating vectors so corners turn to angles. Enough of that and your distance is under counted. I don't know why the Garmin GPS would be better but users say it is.

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