Just wondering

Out walking a steep hill today I just wondered, starting at A climbing
up a steep hill then down the other side to B what will my Gps60csx
show, distance that I have walked or the horizontal distance from A to
B? If the latter then the speed will be reduced as well, as it relies on
satellite positioning I would expect it to be the shorter distance,
however as it also tells me how much climbing I have done perhaps it is
cleverer than that.
--
Residing on low ground in North Staffordshire

I can't comment on what "actually" happens but there is no reason why it
should get distance and speed wrong as height is known to the gps and I
would seriously hope that it is taken into account!

Iain,

On 6/06/2011, Guess posted:



I would agree, except that typically height is pretty inaccurate for
reasons frequently discussed[1] on the GPS newsgroups.

The slope would have to be pretty steep for the difference between
sqrt(x^2 + y^2) and sqrt(x^2 + y^2 + z^2) to be significant.

[1] But AFAICT, not really explained :-)

--
Gene E. Bloch (Stumbling Bloch)

On 6/06/2011, Gene E. Bloch posted:





Let's say x=100, y=120, z=20, or almost a 13% slope.

Ignoring z we get 156.205.
With z, we get 157.480, under a 1% difference.


--
Gene E. Bloch (Stumbling Bloch)

Some time ago I asked Garmin the very same question. I even sent them a
track log and the Mapsource T&WPM elevation plot of the track log. Using the
scale on the X axis and a divider you can determine the total distance you
travel accounting for an elevation gain.
In my case this can be quite significant because on a hike in the mountains
I frequently accend 700 metres.
The Garmin rep I spoke to took a while to respond because he passed the data
on to Garmin Cartography.
Their answer was as follows:

"Thank you for contacting Garmin Cartography and I apologize. I thought
I had already responded. I did check with engineering and the track log
recorded by our units does not take into account vertical distance
travelled. It will only calculate the distance travelled between track
log points based on lat/long. Elevation is not factored in."

So that means that the any speed you measure is not correct either since it
is just measuring the X axis.
That is a distance between two point on an imaginary sphere representing the
surface of the earth.
So even though the GPS may know the elevation it is not that smart.