FLCC> [Fwd: Today's 46 mi ride - MapMyRide.com]
Poulin, Jeffrey
jeffrey.poulin at lmco.com
Mon Apr 7 11:36:40 EDT 2008
Bill,
For a climb to "matter" it depends on the programming of the
instrument.
I have the Ciclosport 414 as well and love it. It is programmed to
only accumulate "ascent" if you go up at least 10'; it does this due to
the sensitivity of the device (it will fluctuate up and down a few feet
just sitting there) and the designers didn't want that to accumulate
ascent. This also means that the C414 doesn't accumulate ascent when
going over small bumps (e.g., culverts) on a flat road.
I also have an altitude watch (Sports Instruments) that displays a 1m
(3') accuracy. It is programmed to accumulate ascent with every 3' of
gain. Not surprisingly, on the same ride the Sports Instrument will
show 30-40% more climbing than the C414.
-jeff
---------
Office: 607-751-6899 | Mobile: 607-725-4493
-----Original Message-----
From: flcc-bounces at icycle.org [mailto:flcc-bounces at icycle.org] On Behalf
Of Bill Goffe
Sent: Monday, April 07, 2008 11:20 AM
To: Moorhead, Michael S
Cc: flcc at icycle.org
Subject: Re: FLCC> [Fwd: Today's 46 mi ride - MapMyRide.com]
To add my own $0.02 worth, I've long used an Ciclosport CM 414 (now
discontinued), which records not only altitude, but also both climb and
descent. It seems to have a very sensitive sensor -- I can see a change
in altitude if I hold it near my feet and then hold it overhead.
As Mike points out, changes in air pressure due to storms can indeed
affect them, but in practice I rarely see that. For the typical ride, it
measures total climb and total descent to 1-2% of each other. As climbs
and descents are measured at different times and in different places, it
give me some confidence that it is "correct." It generally finds less
climbing than what you get with TopoZone.
I tend to think that any climb "matters" as after all you have to move
you and your bike uphill.
Data from topo maps isn't as accurate as you might guess; I'm pretty
sure that TopoZone and all the on-line services use the same dataset
from the U.S. Geological Services (I would think that the military uses
maps from National Geospatial-Intelligence Agency (NGA)
http://www.nga.mil/ .) USGS maps aren't as accurate as you'd think:
http://erg.usgs.gov/isb/pubs/factsheets/fs17199.html .
One would think that measuring total climbing on a ride would be really
straightforward...
- Bill
Mike said:
> I should probably let Shan the GPS guru answer this one, but I think
> it is an interesting question from an engineering standpoint, so I'll
> put in my $0.02.
>
> Most "inexpensive" altimeters use (only) a pressure sensor to
> determine altitude. This is because pressure drops about 1" of Hg
> (mercury) for every 1000 ft gained. The problem, of course, is that
> pressure also fluctuates with weather conditions. I suppose if you
> started a ride on your trainer on a beautiful day where the barometer
> reads 31" Hg and ended it during a thunderstorm when the barometer
> reads 28" Hg, you might have "climbed" 3000 ft.
>
> GPS units typically still use pressure sensors, but they use the
> not-so-accurate vertical GPS position to remove the effect of changing
> atmospheric pressure.
>
> The best way to get the "right answer" is probably using software
> (like
> DeLorme) that uses digital terrain elevation data (DTED) maps. These
> are the very maps that told our beloved cruise missles how to fly
> through canyons to bring democracy to the Iraqis. ;-) The civilian
> versions of these maps probably have 1m accuracy (I really have no
> idea).
>
> The trick, as Andrejs point out, is following a particular set of
rules.
> I personally like the thought that every time my bike hits a 1mm bump
> in the road that it is added to my climb total. Perhaps that's the
> only way I can start getting in some real "climbs" here in Indiana. I
> look pretty silly doing repeats over the highway overpass.
>
> Best,
>
> Mike Moorhead
>
>
> -----Original Message-----
> From: flcc-bounces at icycle.org [mailto:flcc-bounces at icycle.org] On
> Behalf Of Andrejs Ozolins
> Sent: Monday, April 07, 2008 10:11 AM
> To: Ruth E. Sherman
> Cc: flcc at icycle.org
> Subject: Re: FLCC> [Fwd: Today's 46 mi ride - MapMyRide.com]
>
> I can add another climbing number to those: DeLorme's Topo software
> says
>
> you climbed 2,763 feet. It's interesting that your GPS is closer to
> that number than the MapMyRide because GPS units are not particularly
> good at measuring vertical movement. But, behind the disagreement is
> the
>
> fact that your measurement of climbing depends on how you define
> climbing. If you count every single inch of vertical movement as a
> climb, then you'll come up with astronomical figures for a whole ride.
> In practice, the rules can be be defined to give a range of results --
> at what minimum rise to start measuring; what increments to measure,
> etc. Anyway, my impression is that the Topo figure of 2,700 is
> probably closest -- over the years, seeing elevation figures from
> watches and bike computers as well as other people's reports, the
> DeLorme estimate has always been pretty much in the ballpark.
>
> Andrejs
>
> Ruth E. Sherman wrote:
> > Also, there is a big discrepancy between my GPS and MapMyRide's
> estimate
> > of our total ascent - the GPS said we climbed 2321' whereas
> > MapMyRide
> says
> > we climbed 1363'. I prefer to believe the former.
> >
> > ---------------------------- Original Message
> ----------------------------
> > Subject: FLCC> Today's 46 mi ride - MapMyRide.com
> > From: "Ruth E. Sherman" <res6 at cornell.edu>
> > Date: Sun, April 6, 2008 10:42 pm
> > To: flcc at icycle.org
> >
> ----------------------------------------------------------------------
> --
> --
> >
> > After much trial and error and a lot of googling, I was able to
> download
> > today's route from my GPS into a mapping program (most of these
> mapping
> > programs are not well supported for us Mac users). You can access
> > the route at the site below:
> >
> > Ruth Sherman thinks that you should check out the workout he/she
> just
> > plotted online:
> > http://www.mapmyride.com/ride/united-states/ny/ithaca/639350988
> >
> > You can also search for other cycling routes in Ithaca, New
> York:
> > http://www.mapmyride.com/find-ride/united-states/ny/ithaca
> >
> >
>
>
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--
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| Bill Goffe goffe at oswego.edu |
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| Oswego, NY 13126 |
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