GPS Distance errors
06-09-21, 10:50 AM
#101
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In this thread:
You posted this nonsense a mere 3 hours after whining about it!
It was "once" today in this thread. Across the entire thread, it was 7 or 8 times!
Last edited by njkayaker; 06-09-21 at 11:10 AM.
06-09-21, 03:04 PM
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There's an article in Bicycling that has some information why there are GPS errors, and what you can do to avoid them:
How Your GPS Lies to You
How Your GPS Lies to You
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06-10-21, 09:50 AM
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https://www.dictionary.com/browse/whiny
complaining; fretful; cranky:The baby is whiny because he missed his nap.
06-10-21, 09:51 AM
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https://www.dictionary.com/browse/whiny
complaining; fretful; cranky:The baby is whiny because he missed his nap.
Last edited by njkayaker; 06-10-21 at 09:56 AM.
06-10-21, 10:14 AM
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A few weeks ago Jan Heine had a post on his blog about the aero drag of handlebar bags. He was using max speed while coasting down a big hill to determine that. We were curious about that and asked him how he was measuring speed: he was using an iPhone rather than a wheel sensor. If you looked at this max speed, you could tell it was anomalously noisy. We pointed this out and suggested that if he wanted to continue to use max speed (which isn't really that good of a metric, but it was what he was using) he should switch to a wheel sensor. This is about when he decided to cut off comments on his blog posts.
06-10-21, 03:07 PM
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A few weeks ago Jan Heine had a post on his blog about the aero drag of handlebar bags. He was using max speed while coasting down a big hill to determine that. We were curious about that and asked him how he was measuring speed: he was using an iPhone rather than a wheel sensor. If you looked at this max speed, you could tell it was anomalously noisy. We pointed this out and suggested that if he wanted to continue to use max speed (which isn't really that good of a metric, but it was what he was using) he should switch to a wheel sensor. This is about when he decided to cut off comments on his blog posts.
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05-25-23, 08:57 AM
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about halfway down in this thread we did a pretty good discussion of "how GPS works"
How much accuracy do you demand from your bike computer? - Page 2 - Bike Forums
worth a read with some technical details of GPS internals.
your computer is calculating a waypoint every second and then "stitching" those points together to derive speed and distance
the computer does "snap" the position to a road because the raw GPS waypoint has a circular error of about 15 feet best case.
so there are a variety of errors that are possible
worth a read
/markp
How much accuracy do you demand from your bike computer? - Page 2 - Bike Forums
worth a read with some technical details of GPS internals.
your computer is calculating a waypoint every second and then "stitching" those points together to derive speed and distance
the computer does "snap" the position to a road because the raw GPS waypoint has a circular error of about 15 feet best case.
so there are a variety of errors that are possible
worth a read
/markp
