FLCC> [Fwd: Today's 46 mi ride - MapMyRide.com]
Mark Rishniw
mr89 at cornell.edu
Mon Apr 7 11:54:52 EDT 2008
>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.
I climbed Mt Ventoux once, by sitting on my couch and lifting my arm
repetitively! Didn't even raise a sweat, but couldn't raise a beer
that night, either...
>-----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]
>
>
>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 |
> | Department of Economics voice: (315) 312-3444 |
> | SUNY Oswego fax: (315) 312-5444 |
> | 416 Mahar Hall http://cook.rfe.org |
>
> | Oswego, NY 13126 |
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Mark Rishniw
Good health is merely the slowest possible rate at which one can die.
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