60 Csx elevation anomaly ?

Bike ride along St-Lawrence river.


at end of day, GPS indicated a plausible maximum elevation of 116m. But
total climkb of 1347m !!!! (this road is relatively flat, with the
st-lawrence in Ontario and Lake Ontario at about 75-80m).

It was quite windy that day. I was wondering since this altimeter is
based on barometric pressure, is it possible that the wind gust from a
passing truck would have sent the elevation down to -500 and after the
wind gust, it would have risen back to normal ? This would not register
on the maximum elevation, but would raise the total climb by 500m, right ?

How do those barometric altimeters behave in wind, changing weather
conditions , and big gusts from psssing trucks ? Are they immune or does
this change the results significantly ?

Am I the only one who wished there were a "use GPS altitute only" feature ?

On Fri, 20 Aug 2010 17:28:07 -0400, JF Mezei wrote:


What you surmise seems reasonable to me - plus there will also be slower
changes due to weather. Also, as long as the excursions don't go too far
above or below your present altitude, they might still affect the total
altitude change (which IIRC is the sum of the absolute value of the changes
that occur) without showing an unreasonable maximum (or minimum) altitude.

The only problem I see as far as trucks and other short-term gusts go is
that they might not register accurately if they are of a short duration
compared to the sampling interval.

I don't know why I said "accurately". Maybe that word should be omitted,
given the context :-)

--
Gene E. Bloch (Stumbling Bloch)

On Fri, 20 Aug 2010 17:28:07 -0400, JF Mezei


"Total climb" should refer to the total amount of elevation changes over
the distance traveled. For example: My most favorite class-A hiking trail
along a coastline is only about 10 miles in length, stating at sea-level
and ending at sea-level. But it has a total-climb of over 5 miles in
altitude. More than climbing Mt. Everest. It takes about 1.5 to 2 days for
a seasoned hiker to traverse that short "10-miles" of lateral distance,
most of the grade being at least 45 degrees. Though one time, without a
backpack, I managed to do it in one day.

On The 60Csx the TOTAL ASCENT and the TOTAL DECENT parameter can be a
little misleading.

TOTAL ASCENT is actually an accumulation of all the positive gains in
elevation, while

TOTAL DECENT is actually an accumulation of all the drops in elevation.

I questioned this as well after doing quite a bit of hiking in the mountains
where I had a reasonable accurate idea of my real elevation gain

I verified my suspicions by asking Garmin. and that is what I was told in an
email from them.

Suggested to Garmin that the parameter should perhaps correctly be called

ACCUMULATED ELEVATION GAIN and ACCUMULATED ELEVATION LOSS

but that would be too much to be put on the screen.

Hope that clarifies what you might have been reading on you 60Csx.

I had the same experience while hiking in the mountains. There were 2 days
with big wind gusts.
While sitting down for lunch (in de wind....) the total total ascent
counter was jumping forward when the wind was blowing.

At home, I noticed this as spikes in the "show profile" window of
mapsource.

Using the free software GPS-Track-Analyse.NET (http://www.gps-
freeware.de/), I was able to get a better analysis of the track.


Jan