Maps Grids

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

Quoted message said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Do the majority of GPS handhelds (Garmin 60C particularly)
include all the grid and datums that I am likely to
encounter on maps in Europe and Asia ? Is there a list of
these anywhere ?

You should be able to select the grid from a menu of
grids in the set up mode. Have a look around this site>

gpsinformation.netgpsinformation.netOpen ↗

--
Simon Mason Anlaby East Yorkshire. 53°44'N 0°26'W
simonmason.karoo.netsimonmason.karoo.netOpen ↗

The datum for a particular map is usually printed on the
map.

I have an old Magellan 315 and that has lots of different
datums and a user defined datum, so I'm sure a more modern
gps will have what you need. You might also be intersted in
looking at www.gpsu.co.uk

Regards, Neil

in message <[email hidden]>, David

(') said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Do the majority of GPS handhelds (Garmin 60C particularly)
include all the grid and datums that I am likely to
encounter on maps in Europe and Asia ? Is there a list of
these anywhere ?

The IHO have a list of those used on marine charts, yes
(although I can't find it just now). A number of different
ellipsoids and datums are used because the earth is not a
perfect elipsoid and different ones are better
approximations in different parts of the world (furthermore,
the earth isn't solid, it's squishy, and bits of 'solid
earth' like for example Britain move up and down with
respect to the centre of the earth by about one metre in the
course of a normal day).

The OS grid has uses an ellipsoid called Airy1830 which as
far as I know is special and not used for anything else
(there's also an ellipsoid called OSGB30 which may be the
same as Airy1830 but I can't find anything which explicitly
says so). Differences between ellipsoids can lead to errors
of position of up to about 250 metres.

I suspect that many if not most commercial land maps are not
sufficiently accurate for these differences to matter,
particularly in less developed and less populated parts of
the world.

A useful introductory document is here: <URL:http://www.gps-
.gov.uk/additionalInfo/images/A_guide_to_coord.pdf>

--
[email hidden] (Simon Brooke)
jasmine.org.uk~simonOpen ↗

'graveyards are full of indispensable people'

[email hidden] (David) wrote in
:"]news:[email hidden]:

Quoted message said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Actually, there's a bit more to it than that.

Assume for a moment that your paper map has
latitude/longitude markings along the map's edges(neat
lines). It might also have a grid on the map that connects
the lat/lon tick marks.

If you have your GPS on, and receiving signals, and set to
display it's position in lat/lon format, and you want to see
where that puts you on the paper map, you need to know what
datum(s) are being used. In practical terms, what this means
is reading the paper map to determine what datum it uses,
then setting your GPS to the same datum, then using the
position reported by the GPS.

Even if your paper map has lat/lon tick marks on the neat
lines, it may also have a grid printed on the map, such as a
UTM (Universal Transverse Mercator) grid. To make use of
this grid you still need to be using the correct datum in
your GPS. You just change your GPS's "position format"
setting from lat/lon to, in this example, UTM, and then read
your position in UTM coordinates and use them in conjunction
with the map's UTM grid.

Although it's a bit 'US-centric', you might be interested in
Garmin's "Using a Garmin GPS with Paper Maps" manual.
There's a link in the "GPS Resources" section on the GPS
page on my website.

--
Dave Patton Canadian Coordinator, Degree Confluence Project
confluence.orgconfluence.orgOpen ↗ My website:
members.shaw.cadavepattonOpen ↗

David said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Do the majority of GPS handhelds (Garmin 60C particularly)
include all the grid and datums that I am likely to
encounter on maps in Europe and Asia ? Is there a list of
these anywhere ?

Can anyone recommend good cycling maps that include such
grids to cover Alsace in France ?

Many thanks for help Dave

You can visit our website on
lesrandoactifs.fr.stlesrandoactifs.fr.stOpen ↗ dedicate to mountain bike
in south of france Visit to ign.frign.frOpen ↗ if you dont
found your answer on the site mail us .

best regards

LUC

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

Quoted message said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Do the majority of GPS handhelds (Garmin 60C particularly)
include all the grid and datums that I am likely to
encounter on maps in Europe and Asia ? Is there a list of
these anywhere ?

Can anyone recommend good cycling maps that include such
grids to cover Alsace in France ?

Many thanks for help Dave

Andy

You have drawn several replies about grids.

For maps I suggest that you look at the Michelin 1:200 000
or newer 1:180 000 and 1:150 000 maps, which I have found
quite satisfactory for cycling on minor roads. I have a ten
year old one with latitude and longitude gridlines at 10'
(ten minute) intervals. See viamichelin.comviamichelin.comOpen ↗ .
These maps are widely available in France at supermarkets
and petrol stations. They are also obtainable in UK at
£3.99. One supplier is themapshop.co.ukthemapshop.co.ukOpen ↗ .

For more detailed (and more expensive) maps, more like
Britain's Ordnance Survey maps, see the 1:25 000 maps of the
French Institut Geographique National ign.frign.frOpen ↗ .
The newer maps are marked Compatible GPS and have UTM
gridlines in blue using the datum WGS 84. I have used these
maps for skiing off the beaten track. IGN do summer and
winter versions for some of the alpine areas. I expect (but
cannot confirm) that the summer ones include pistes
cyclables (cross country cycle paths). The maps typically
cost 9 Euro and are harder to find. In UK
themapshop.co.ukthemapshop.co.ukOpen ↗ sell them.

Mark I

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

Quoted message said:

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

Quoted message said:

I am new to GPS, and have discover that if I want to use
paper maps, then I will need to establish the grid on
which the map is based.

Do the majority of GPS handhelds (Garmin 60C
particularly) include all the grid and datums that I am
likely to encounter on maps in Europe and Asia ? Is
there a list of these anywhere ?

Can anyone recommend good cycling maps that include such
grids to cover Alsace in France ?

Many thanks for help Dave

Andy

You have drawn several replies about grids.

For maps I suggest that you look at the Michelin 1:200 000
or newer 1:180 000 and 1:150 000 maps, which I have found
quite satisfactory for cycling on minor roads. I have a
ten year old one with latitude and longitude gridlines at
10' (ten minute) intervals. See viamichelin.comviamichelin.comOpen ↗
. These maps are widely available in France at
supermarkets and petrol stations. They are also obtainable
in UK at £3.99. One supplier is
themapshop.co.ukthemapshop.co.ukOpen ↗ .

For more detailed (and more expensive) maps, more like
Britain's Ordnance Survey maps, see the 1:25 000 maps of
the French Institut Geographique National
ign.frign.frOpen ↗ . The newer maps are marked Compatible
GPS and have UTM gridlines in blue using the datum WGS 84.
I have used these maps for skiing off the beaten track.
IGN do summer and winter versions for some of the alpine
areas. I expect (but cannot confirm) that the summer ones
include pistes cyclables (cross country cycle paths). The
maps typically cost 9 Euro and are harder to find. In UK
themapshop.co.ukthemapshop.co.ukOpen ↗ sell them.

Mark I

-------------------------------

If you use maps that have a scale of 1:100,000 or smaller
(1:250,000) the particular "datum" of a country is more or
less only an academic point of interest. The larger the
scale of your map (IGN or Ordnance Survey), the more
important the datum details become. The UK, Italy and
Germany use a Transverse Mercator projection that a Garmin
will accommodate. The Garmin will of course accommodate
UTM. However, most other countries in Western Europe do NOT
use the Transverse Mercator on large-scale maps and
therefore the Garmin units are useless except for plotting
latitude and longitude coordinates on those maps. Local
Grid systems based on the oblique stereographic and the
Lambert conformal conic are only attainable with a Magellan
- Garmin won't do it.

If you stay with small-scale maps, such minutiae can
be ignored.

Cliff Mugnier LOUISIANA STATE UNIVERSITY

Prof. Cliff Mugnier said:

The UK, Italy and Germany use a Transverse Mercator
projection that a Garmin will accommodate. The Garmin will
of course accommodate UTM. However, most other countries
in Western Europe do NOT use the Transverse Mercator on
large-scale maps and therefore the Garmin units are
useless except for plotting latitude and longitude
coordinates on those maps. Local Grid systems based on the
oblique stereographic and the Lambert conformal conic are
only attainable with a Magellan - Garmin won't do it.

This is also true for State Plane coordinates in the US,
see: gpsinformation.netstate plane mag.htmlOpen ↗
--
Jack

Get general GPS information at:
gpsinformation.netgpsinformation.netOpen ↗