Which are the coordinates of the magnetic North and Southpole?
Ed McNierney
was at 78.3 degrees North, 104.0 degrees West. It is moving north about
15km per year, and on any one day wanders about its average location by as
much as 80km (!)
The Center for Astrophysical Research in Antarctica reported the south
magnetic pole at 65.3 degrees South 140.0 degrees East in 1986.
Both values should be close enough for you unless you're cruising arctic
Canada or piloting your boat across the Weddell Sea...
- Ed
renevers <rene...@xs4all.be> wrote in message
news:92862847...@smtp.xs4all.be...
> For calibrating purposes of compasses I want to check the magnetic course
> and its deviation with my Garmin III.
> Entering the Magnetic Northpole as a waypoint and effecting a "goto" to
it
> makes your (moving) compass screen a real compass screen. Now I can
compare
> the influence of the iron mass of my car and boat and the influence of the
> course direction and boat inclination angle.
>
> So I need the coordinates.
>
> renevers
>
>
Dave Martindale
>Entering the Magnetic Northpole as a waypoint and effecting a "goto" to it
>makes your (moving) compass screen a real compass screen. Now I can compare
>the influence of the iron mass of my car and boat and the influence of the
>course direction and boat inclination angle.
You seem to assume that a magnetic needle always points directly towards
the magnetic north pole. That's roughly correct, but probably not all
that accurate. If that model was accurate, then the magnetic variation
on the earth's surface would be a simple and smooth function of your
current position and the position of the pole. If you look at a real
map of magnetic variation, the lines of equal variation are just not
that smooth. So there must be additional sources of variation in
the variation (!), and magnetic compasses don't always point exactly
at magnetic north.
Dave
renevers
and its deviation with my Garmin III.
makes your (moving) compass screen a real compass screen. Now I can compare
the influence of the iron mass of my car and boat and the influence of the
course direction and boat inclination angle.
So I need the coordinates.
renevers
Dave Ulmer
headings'
and compare that to the compass? If I remember correctly the magnetic
deviations are sent down from the GPS sattlites to keep the gps's magnetic
heading information correct.
Dave...
renevers <rene...@xs4all.be> wrote in message
news:92862847...@smtp.xs4all.be...
Jack Yeazel
>
> I may be wrong, but couldn't you just set your gps to read 'magnetic
> headings'
> and compare that to the compass? If I remember correctly the magnetic
> deviations are sent down from the GPS sattlites to keep the gps's magnetic
> heading information correct.
No, GPS units have a stored lookup table to determine the
Magnetic Variation for the current position... These lookup
tables are for a particular date and become out of date
themselves after a few years...
Garmin just updated their table to sometime in the next
century, but I didn't record the date...
--
Jack
Get general GPS information at http://joe.mehaffey.com/
Peter Bennett
>For calibrating purposes of compasses I want to check the magnetic course
>and its deviation with my Garmin III.
>Entering the Magnetic Northpole as a waypoint and effecting a "goto" to it
>makes your (moving) compass screen a real compass screen. Now I can compare
>the influence of the iron mass of my car and boat and the influence of the
>course direction and boat inclination angle.
Unfortunately, the earth's magnetic field is not nice and uniform, so your
plan won't work reliably.
I suggest you look at a map or nautical chart that shows magnetic variation
for your location, and use that value.
--
Peter Bennett, VE7CEI
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver-webpages.com/van-ps
Ken & Cheri Nelson
uniform, you could just work backwards from two points on earth, find the
intersection of two lines going Mag North ( or Mag South ), and there you
are. I went though this just for the heck of it
and every set of plots intersected in a slightly different place. The tables
in my old Magellan 2000 were more accurate than using the current physical
position of the North Mag pole.
Note also that the distortions are severe enough that South Mag pole is NOT
exactly opposite. In fact, it's considerable off exactly opposite. But it's
an interesting exercise.. try it!
Ken
Peter Bennett <pet...@interchange.ubc.ca> wrote in message
news:3762b2f8....@news.supernews.com...
Peter Kellaway
degrees & minutes
http://unixb.nerc-murchison.ac.uk/gifs/igrf.html
or
http://www.geolab.nrcan.gc.ca/geomag/e_cgrf.html
or
http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl
the Canadian site has links to relevant programs/source code
the UK site will if requested email the results with a small map of the
requested area
Sam Wormley
>
> I may be wrong, but couldn't you just set your gps to read 'magnetic
> headings'
> and compare that to the compass? If I remember correctly the magnetic
> deviations are sent down from the GPS sattlites to keep the gps's magnetic
> heading information correct.
>
> and its deviation with my Garmin III.
> Entering the Magnetic Northpole as a waypoint and effecting a "goto" to it
> makes your (moving) compass screen a real compass screen. Now I can compare
> the influence of the iron mass of my car and boat and the influence of the
> course direction and boat inclination angle.
>
>
> renevers
The magnetic variation (declination) pattern is too complex and location
specific to be sent economically from GPS satellites and would be orders
of magnitude greater than the current GPS message that is sent.
Information about the GPS message is available from numerous sources
including:
http://206.65.196.30/gps/geninfo/gpsdocuments/gpsuser/gpsuser.pdf
http://www.navcen.uscg.mil/gps/geninfo/gpsdocuments/sigspec/default.htm
http://www.navcen.uscg.mil/gps/geninfo/gpsdocuments/icd200/icd200c.pdf
>Magnetic declination information (like the geoid undulation information to
>calculate altitude above Mean Sea Level) is in the form of lookup tables with
>interpolation. For information about magnetic declination (variation) see:
http://www.ngdc.noaa.gov/seg/potfld/geomag.html
http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl
http://swdcdb.kugi.kyoto-u.ac.jp/igrf/
http://www.cam.org/~gouletc/decl_faq.html
-Sam Wormley
Steve Uliasz
>
> Dave Ulmer wrote:
> >
> > I may be wrong, but couldn't you just set your gps to read 'magnetic
> > headings'
> > and compare that to the compass? If I remember correctly the magnetic
> > deviations are sent down from the GPS sattlites to keep the gps's magnetic
> > heading information correct.
>
> Magnetic Variation for the current position... These lookup
> tables are for a particular date and become out of date
> themselves after a few years...
> Garmin just updated their table to sometime in the next
> century, but I didn't record the date...
> --
> Jack
>
> Get general GPS information at http://joe.mehaffey.com/
Are the lookup tables contained in the firmware upgrades that I have
been faithfully downloading for my 12XL (currently 4.54)?
--- SJU
Peter Kellaway
Phil Wheeler
Calif., it takes about 25 yrs to see a one degree change. Of course,
closer to the magnetic poles, it will change more rapidly.
Phil
Brent Geery wrote:
>
> On Sun, 6 Jun 1999 05:38:33 -0700, "Dave Ulmer"
> <dave...@sprintmail.com> wrote:
>
> >If I remember correctly the magnetic
> >deviations are sent down from the GPS sattlites to keep the gps's magnetic
> >heading information correct.
>
> Nope. It's just a table built into the GPS. I wonder how long this
> table is good for before it's significantly in error, and can it be
> updated via a firmware update, or is it in ROM like the cities
> database.
>
> BRENT
Leo Hamulczyk
>
> You seem to assume that a magnetic needle always points directly towards
> the magnetic north pole. That's roughly correct, but probably not all
> that accurate.
It's definitely not correst. I have a good diagram in an atlas showing a
map centred somewhere below the north pole on Longitude 0 deg, showing
lines pointing in the direction of the magnetic field. I would send it,
except I don't have a scanner handy (not until the weekend).
Leo Hamulczyk
l...@i-o.net.au
renevers
north pole" and the function within the G3 setup to point to the mag North,
to see wether there is a difference.
I once flew over the Northpole from (fromAmsterdam to Vancouver), I think I
was very near the Mag Northpole somewhere s near Baffin Island. I watched my
Casio-Compass watch getting lost near the place where I expected the pole,
so .....
I think this is a "strategic" and interesting waypoint that should be on
everybodies GPS as the real Northpole is one. I have already entered the
real Northpole as (89.9999, 89.9999)
It is quicker to enter the "Goto Northpole" specially when you are just
driving around in the car and you just use the compass screen in the G3 as a
kind of direction reference like a compass on a boat. The compassscreen
arrow is than always pointing North like this. I want to do the same with
the mag Northpole.
For muslims I have entered Mekka in my GPS so I can help them pointing to
the right pray direction.
Can somebody help me with the coordinates for the East and Westpole aswell?
renevers
----- Original Message -----
From: Dave Martindale <da...@flip.cs.ubc.ca>
Newsgroups: sci.geo.satellite-nav
Sent: Sunday, June 06, 1999 8:08 AM
Subject: Re: Which are the coordinates of the magnetic North and Southpole?
> "renevers" <rene...@xs4all.be> writes:
> >Entering the Magnetic Northpole as a waypoint and effecting a "goto" to
it
> >makes your (moving) compass screen a real compass screen. Now I can
compare
> >the influence of the iron mass of my car and boat and the influence of
the
> >course direction and boat inclination angle.
>
> You seem to assume that a magnetic needle always points directly towards
> the magnetic north pole. That's roughly correct, but probably not all
David Ness
you may want to waypoint that (but watch out for the `Revenooers' if
you go there...)
renevers wrote:
>
....
Bob Martin
renevers wrote:
>
> For calibrating purposes of compasses I want to check the magnetic course
> and its deviation with my Garmin III.
> Entering the Magnetic Northpole as a waypoint and effecting a "goto" to it
> makes your (moving) compass screen a real compass screen. Now I can compare
> the influence of the iron mass of my car and boat and the influence of the
> course direction and boat inclination angle.
>
> So I need the coordinates.
>
> renevers
It's moving constantly. I found numerous references, best ones at
www.trimble.com
Bob
JF Mezei
> I once flew over the Northpole from (fromAmsterdam to Vancouver), I think I
> was very near the Mag Northpole somewhere s near Baffin Island. I watched my
> Casio-Compass watch getting lost near the place where I expected the pole,
> so .....
Not quite. The magnetic north pole is nearer to Resolute Bay which is quite a
bit north of baffin island. You would barely have gone north or the arctic
circle on a AMS-YVR run. Also, throughout the arctic, magnetic compasses are
totally unreliable, even as far south as the arctic circle.
To see a path of AMS-YVR, :
http://www.chicago.com/cgi-bin/gc?PATH=ams-yvr&RANGE=&PATH-COLOR=&PATH-UNITS=mi&RANGE-STYLE=best&RANGE-COLOR=&MAP-STYLE=
Now, onto the real stuff:
Set my GPS-II+ to mag north. Set it to simulator.Set to about 80 degrees
north, 120 west.
Set my heading to "0" and speed to 999 km/h. Ok, maybe not so fast :-)
The GPS seems to first convert your requested direction to a real direction,
and keeps that true heading. So, as you move, your relative heading to the mag
pole changes. I tried to narrow down to where the mag pole is (according to
the GPS), but I don't have time yet to do it.
According to a Northwest terrtories map (actually that part is now called
Nunavut) of the early 90s:
The magnetic north pole is roughly at 76 degrees north, 102 degrees west. At
the northern tip of Bathurst island. Nearest commercial Airport at Resolute
Bay (YRB) which is at 74°15"n - 94°50"w
Bob Martin
Well, I've got it straight now. If you go far enough north, your
compass
needle's north pointing end will start to point downwards into the
earth, and when you reach the north pole it will point straight
down, which is the actual direction to the south pole, however
the south pointing end of your compass needle will point
straight up which is the opposite direction from the south
pole. Obviouly, if you're lost and your compass doesn't
work, you MUST be at the north pole, so you can get back
to wherever you started by going south.
Bob
Keith
with the wandering magnetic North pole...
Keith
--------------------------------------------------------------------
The response:
We produce magnetic reference field models for calculating magnetic
declination every five years, so later this year we will be starting the
year 2000 version, which will keep you going until 2005.
As for the north magnetic pole, its motion simply isn't predictable for more
than a short time interval. It has been moving north or north-westerly for
more than a century, and there is no indication that this is going to
change. However, changes in the magnetic field can occur quite suddenly,
within a couple of years, so the magnetic pole could undergo a sudden change
in direction with very little warning. Something like this probably
happened in the mid-nineteenth century; the pole had been moving south and
suddenly turned and started to move north.
This unpredictability is one of the reasons for re-surveying its position
every few years.
Regards
Larry Newitt
Geomagnetic Laboratory
--------------------------------------------------------------------------
> My original message
> From: Keith X > Sent: Tuesday, June 08, 1999 5:11 AM
> To X > Subject: North Pole Drift
>
> Hi Larry
> I was taking a look at magnetic deviation at
> http://www.geolab.nrcan.gc.ca/geomag/e_cgrf.html I see that it does not
> calculate deviations past the year 2001. I was just curious about where
> the north pole will be decades or centuries from now.... wondering if the
> magnetic pole just "wanders" or if it the general drift keeps going...
> Thanks - Keith
>
-----------------------------------------------------------------
JF Mezei <jfmezei...@videotron.ca> wrote in message
news:375C817A...@videotron.ca...