GPS experts

Ride-A-Lot said:

Had a beautiful night ride this evening in the pines. The full moon
was stunning and lit the place up so well, you didn't even need
lights. Unfortunately, we had to cut a couple of miles off the out
and back due to the recent snow melt. No mud (there never is and the
trails are never soft) but a foot of standing water where the
boardwalk is supposed to be.

Anyway, I brought the GPS with me again and found this strange anomaly
in Google Earth:

http://www.pchospital.net/jdevil/JerseyDevil.kml

You owe me 4 seconds of life.

Bill Sornson said:

Ride-A-Lot said:

Had a beautiful night ride this evening in the pines. The full moon
was stunning and lit the place up so well, you didn't even need
lights. Unfortunately, we had to cut a couple of miles off the out
and back due to the recent snow melt. No mud (there never is and the
trails are never soft) but a foot of standing water where the
boardwalk is supposed to be.

Anyway, I brought the GPS with me again and found this strange anomaly
in Google Earth:

http://www.pchospital.net/jdevil/JerseyDevil.kml

You owe me 4 seconds of life.

The subject says... GPS experts

Since when are you a GPS expert? I'll make it up to you anyway.

1 1000 2 1000 3 1000 4 1000

There, we're even.

--
o-o-o-o Ride-A-Lot o-o-o-o
www.schnauzers.ws

Isn't that Lebanon State Forest near Browns Mills and
the beach lake? Been a life time since I was there last.

Quoted message said:

Isn't that Lebanon State Forest near Browns Mills and
the beach lake? Been a life time since I was there last.

Yes. Now called Brendan Byrne State Forest (they keep naming things
after him and taking it away - the meadowlands arena, the state
aquarium, and now the forest). We start in Ong's Hat, just south of
Brown's Mills. You can literally ride for a 100 miles if you wanted to
as three state forests (all part of the Pinelands National Reserve) hook
up to each other. We typically ride east along the B****a trail (it's
poached) for 9 miles, then do the white trail (Mount Misery) for an 8
mile loop), and then back out the way we came. You could follow the
B****a trail for 50 miles of singletrack through all three parks and
then do miles worth of off-shoots from there (our new trails in Wharton
State Forest) are an example of this.

--
o-o-o-o Ride-A-Lot o-o-o-o
www.schnauzers.ws

"Ride-A-Lot" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Had a beautiful night ride this evening in the pines. The full moon was
stunning and lit the place up so well, you didn't even need lights.
Unfortunately, we had to cut a couple of miles off the out and back due to
the recent snow melt. No mud (there never is and the trails are never
soft) but a foot of standing water where the boardwalk is supposed to be.

Anyway, I brought the GPS with me again and found this strange anomaly in
Google Earth:

http://www.pchospital.net/jdevil/JerseyDevil.kml

This is an out and back trail, so I would think that the tracks should
overlap. Can the GPS be that off?

That looks like a pretty good overlap to me. A lot of factors can contribute
to variations: how many satellites your receiver can see and how those
satellites are positioned around the particular landscape that surrounds
you. The satellites are always moving, and so are you. But trees, mountains,
hills, and manmade objects aren't going anywhere. Sometimes the signal from
a satellite gets bounced around or lost altogether. Weather conditions can
also affect reception.

Shawn said:

Gary Millman said:

GARTINsux wrote:

Quoted message said:

Quoted message said:

Quoted message said:

You don't post until you've ridden some rock gardens.

Quoted message said:

Quoted message said:

You really are a [censored] arn't you.

Quoted message said:

It wishes!

It fails to learn how to SNIP!!!!!!!!!!!!!!!!!!!!!!!!!!!

Bll wrt:

SNP!

Ops, my bd.

Shwn

Shawn said:

Bll wrt:

SNP!

Ops, my bd.

Shwn

Smrtss.

<g>

Bill Sornson said:

Shawn said:

Bll wrt:

SNP!

Ops, my bd.

Shwn

Smrtss.

<g> <--- that was supposed to be an evil grin

Bll "crsd vwls" S.

Ride-A-Lot said:

This is an out and back trail, so I would think that the tracks should
overlap. Can the GPS be that off?

Even without Selective Availability anymore, it's really only accurate
to within three meters if you have a 3-dimensional reading from getting
at least four satellites in the constellation of 26 (2 spares in case
one malfunctions beyond tele-repair). If you don't get a 3-dimensional
reading, it can be off up to 30 meters +.

Now go buy a map and become a true cartographer.

JD

JD said:

Ride-A-Lot wrote:
Now go buy a map and become a true cartographer.

Heh, I did just that, but it looks like [censored]. I bought some of that
blank National Geographic topo paper.

--
o-o-o-o Ride-A-Lot o-o-o-o
www.schnauzers.ws

"JD" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Ride-A-Lot said:

This is an out and back trail, so I would think that the tracks should
overlap. Can the GPS be that off?

Even without Selective Availability anymore, it's really only accurate
to within three meters if you have a 3-dimensional reading from getting
at least four satellites in the constellation of 26 (2 spares in case
one malfunctions beyond tele-repair). If you don't get a 3-dimensional
reading, it can be off up to 30 meters +.

Now go buy a map and become a true cartographer.

JD

More like 5 m if your lucky

Frugal Joe said:

"JD" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Ride-A-Lot said:

This is an out and back trail, so I would think that the tracks should
overlap. Can the GPS be that off?

Even without Selective Availability anymore, it's really only accurate
to within three meters if you have a 3-dimensional reading from getting
at least four satellites in the constellation of 26 (2 spares in case
one malfunctions beyond tele-repair). If you don't get a 3-dimensional
reading, it can be off up to 30 meters +.

Now go buy a map and become a true cartographer.

JD

More like 5 m if your lucky

I was just relaying the party line on it. I wouldn't count on even 5m
on a typically good mountain bike trail because of the terrain and
trees.

JD

"JD" <[email hidden]> wrote in message
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Quoted message said:

Frugal Joe said:

"JD" <[email hidden]> wrote in message
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Quoted message said:

Ride-A-Lot wrote:
> This is an out and back trail, so I would think that the tracks should
> overlap. Can the GPS be that off?

Even without Selective Availability anymore, it's really only accurate
to within three meters if you have a 3-dimensional reading from getting
at least four satellites in the constellation of 26 (2 spares in case
one malfunctions beyond tele-repair). If you don't get a 3-dimensional
reading, it can be off up to 30 meters +.

Now go buy a map and become a true cartographer.

JD

More like 5 m if your lucky

I was just relaying the party line on it. I wouldn't count on even 5m
on a typically good mountain bike trail because of the terrain and
trees.

JD

You are exactly right. And as you know, trails if mapped, are not mapped to
that precision.

"JD" <[email hidden]> wrote in message
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Quoted message said:

I was just relaying the party line on it.

JD

Thanks for passing off BS as personal knowledge

Frugal Joe said:

"JD" <[email hidden]> wrote in message
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Quoted message said:

Frugal Joe said:

"JD" <[email hidden]> wrote in message
news:[email hidden]...
>
> Ride-A-Lot wrote:
>> This is an out and back trail, so I would think that the tracks should
>> overlap. Can the GPS be that off?
>
>
> Even without Selective Availability anymore, it's really only accurate
> to within three meters if you have a 3-dimensional reading from getting
> at least four satellites in the constellation of 26 (2 spares in case
> one malfunctions beyond tele-repair). If you don't get a 3-dimensional
> reading, it can be off up to 30 meters +.
>
> Now go buy a map and become a true cartographer.
>
> JD
>

More like 5 m if your lucky

I was just relaying the party line on it. I wouldn't count on even 5m
on a typically good mountain bike trail because of the terrain and
trees.

JD

You are exactly right. And as you know, trails if mapped, are not mapped to
that precision.

Road and trail systems with in the DoA and DoI are often mapped to sub
meter (centerline) accuracy, although printed maps are never produced
with this accuracy.

Both the BLM and NPS have been mapping trails with submeter accuracy
for years. Even with SA Trimble units allowed for submeter precision,
and with post processing of the data, submeter accuracy. The standard
unit for the NPS for Fire, R/T and L.E. duty is a Trimble WAAS DGPS
unit. The dataloggers are set up for multipath rejection, and post
processing takes care of signal delay errors, ambiguity problems,
doppler shift ...

Given that R/T generally uses GPS and GIS as management tools and not
as Navigational tools, data collection generally takes place only when
a low DOP values are given, so it is not uncommon to have a sub 1m
2drms even before post processing. Of course, given that the NMAS for a
map at 1:24,000 is + or - 40.00 feet ... the data collected is most
often left in a GIS rather than printing it on to some USGS base map
(and DEM's only make it worse).

R
ATONR/squint 1994-2000.

And you should see what we have been doing with Kinematic Positioning
and Centroids.

Frugal Joe said:

"JD" <[email hidden]> wrote in message
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Quoted message said:

I was just relaying the party line on it.

JD

Thanks for passing off BS as personal knowledge

If you think I had to research that to get an answer, you are sadly
mistaken. I have written RFPs for GPS based AVL systems in a public
safety application. It's all personal knowledge. Maybe if you stood
in my face and tried to grill me on GPS, you could see this for
yourself. Then again, you are a gutless POS and that would never
happen.

JD

"JD" <[email hidden]> wrote in message
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Quoted message said:

Quoted message said:

Quoted message said:

I was just relaying the party line on it.

If you think I had to research that to get an answer, you are sadly
mistaken. I have written RFPs for GPS based AVL systems in a public
safety application. It's all personal knowledge. Maybe if you stood
in my face and tried to grill me on GPS, you could see this for
yourself. Then again, you are a gutless POS and that would never
happen.

JD

But you gave the WRONG answer which you said you were relaying as "the party
line".

Now you know it?

How many times have you flamed folks for giving misinfo as the "party line"

You're soooo brave.

"JD" <[email hidden]> wrote in message
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Quoted message said:

Frugal Joe said:

"JD" <[email hidden]> wrote in message
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Quoted message said:

I was just relaying the party line on it.

JD

Thanks for passing off BS as personal knowledge

If you think I had to research that to get an answer, you are sadly
mistaken.

Better to research and get the right answer!

Quoted message said:

I have written RFPs for GPS based AVL systems in a public
safety application.

You probably bought the wrong stuff. Way to toe the party line you tool.

Quoted message said:

JD