Magellan GPS - Explorist 400 calculating distances

Author

Explorist 400 calculating distances

Lobo

2007-03-26, 4:33 am

Is it possible to use a 400 to pace off distances in meters or yards?
What I'd like to be able to do is accurately pace off 50 or 100 yards/
meters while holding the unit.

Thanks in advance.

Jack Erbes

2007-03-26, 7:33 am

Lobo wrote:

> Is it possible to use a 400 to pace off distances in meters or yards?
> What I'd like to be able to do is accurately pace off 50 or 100 yards/
> meters while holding the unit.
>

You could place a waypoint, start a Goto to that waypoint, then move
away from it and use the distance reading to get a distance away but it
would only be an approximate distance, not very accurate.

You are always going to have some amount of error in your position, that
is often called the Estimated Position Error or EPE and is usually
expressed as a radius in feet.

At best, after staying in one position for several minutes of more and
holding the receiver in a stable position, you may get your EPE down to
10-15 feet or so. So that would give you an approximate total error of
+/- 20 to 30 feet between two points of an measured distance.

Jack

--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

Al Rodecap

2007-03-26, 10:33 am

IJack Erbes wrote:
> Lobo wrote:
>
>
> You could place a waypoint, start a Goto to that waypoint, then move
> away from it and use the distance reading to get a distance away but it
> would only be an approximate distance, not very accurate.
>
> You are always going to have some amount of error in your position, that
> is often called the Estimated Position Error or EPE and is usually
> expressed as a radius in feet.
>
> At best, after staying in one position for several minutes of more and
> holding the receiver in a stable position, you may get your EPE down to
> 10-15 feet or so. So that would give you an approximate total error of
> +/- 20 to 30 feet between two points of an measured distance.
>
> Jack
I've got an Explorist 400 and I've found that the track log is more
accurate than the display. Why I'm not sure but from comparisons I did
last year to a pedometer over the same track for several days had the
track log and pedometer working within a few percent of each other. The
on screen display was a different issue.

I posted a question and subsequent information on Sept 6 & 9 of 2006.

Hope this helps.

Al

Al Rodecap

2007-03-26, 10:33 am

Lobo wrote:
> Is it possible to use a 400 to pace off distances in meters or yards?
> What I'd like to be able to do is accurately pace off 50 or 100 yards/
> meters while holding the unit.
>
> Thanks in advance.
>
I've got an Explorist 400 and I've found that the track log is more
accurate than the display. Why I'm not sure but from comparisons I did
last year to a pedometer over the same track for several days had the
track log and pedometer working within a few percent of each other. The
on screen display was a different issue.

As Jack stated, there will be some error. There are really accurate GPS
units and the local surveyors have something that is GPS driven that
they use.

I posted a question and subsequent information on Sept 6 & 9 of 2006.

Hope this helps.

Al

Ron Hunter

2007-03-26, 3:33 pm

Lobo wrote:
> Is it possible to use a 400 to pace off distances in meters or yards?
> What I'd like to be able to do is accurately pace off 50 or 100 yards/
> meters while holding the unit.
>
> Thanks in advance.
>

You have to understand that the measuring accuracy may be only a few
inches if enough sats. are in range, BUT the accuracy of the display is
only about 50 feet.

Pieter Litchfield

2007-03-27, 10:33 am

There are a number of sources of error in GPS - particularly when using a
"retail" GPS. There could be poor geometry of the satellites in view.
There could be poor atmospherics that result in signal degradation. There
could be wet leaf canopy or multi-path resulting from buildings or hidden
signals resulting from canyon walls.

Yes - you can certainly reset the trip odometer on your GPS and pace off a
distance, but don't expect pinpoint accuracy. If you are looking for
accuracy of +/- 1 foot in 50 yards, the answer is probably "not today." I
routinely measure trails that are between .1 and 1 miles long for use in
running events, and where you must be assured of accuracy, a measuring wheel
or tape is a better bet. It is consistent and predictable.

"Ron Hunter" <rphunter@charter.net> wrote in message
news:mLGdnR6coLMTsJX
bnZ2dnUVZ_gydnZ2d@gi
ganews.com...
> Lobo wrote:
>
> You have to understand that the measuring accuracy may be only a few
> inches if enough sats. are in range, BUT the accuracy of the display is
> only about 50 feet.

LinkBot