GPS Question

You can switch it on just to fix your position, but it can take 5 mins
or more to get a good fix.

druidh

In article <[email hidden]>, aj
<[email hidden]> writes

Quoted message said:

i dont have a GPS but cant you just switch one on if you are unsure of your
position to get a grid reference & keep it switched off the rest of the time
& therefore not getting lost anyway..or isnt it as simple as that?
thanks.

Yes you can. However when first switched on the location can be a
considerable distance out for the first couple of minutes. The error is
increased by changes of altitude (few hundreds of metres) or large
distances moved (few hundreds of KM) since last used. As long as you let
it settle down with a good view of the sky for a couple of minutes it
should be within 10m of your location reliably.

--

Dominic Sexton

aj said:

i dont have a GPS but cant you just switch one on if you are unsure of your
position to get a grid reference & keep it switched off the rest of the time
& therefore not getting lost anyway..or isnt it as simple as that?

You can just switch on and get a reference, but you have to be in view
of at least 3 staellites. In the open this is more or less guaranteed,
at least within a short space of time, but in dense forest or gorges and
gullies etc., if you're out of line of sight of satellites then you're
snookered.
If the unit is left on it tends to keep a signal better than if it's
just turned on, which is worth noting in poor reception areas. Of
course, this chews the batteries rather more.

And of course navigation is more than just about knowing where you are.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

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

Quoted message said:

You can switch it on just to fix your position, but it can take 5 mins
or more to get a good fix.

druidh

that doesnt seem long druidh,i could buy the cheapest to keep in my sack
just in case!

yes thats what i do and on the scottish hills i have never had to wait for
more than 1 or 2 minutes who counts time when you are on the hills anyway
"druidh" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

You can switch it on just to fix your position, but it can take 5 mins
or more to get a good fix.

druidh

Bitstring <[email hidden]>, from the wonderful person
Peter Clinch <[email hidden]> said
<snip>

Quoted message said:

And of course navigation is more than just about knowing where you are.

Indeed. By far the most fun bit is getting back to your PC and seeing
where you've actually BEEN (and whether it bears any faint resemblance
to where you planned to go)!

--
GSV Three Minds in a Can
Google may be your friend, but groups.google.com posters definitely aren't.

Quoted message said:

As long as you let it settle down with a good view of the sky for a couple of minutes it
should be within 10m of your location reliably.

Yes, one hopes it would be, most of the time.

But not all the time.

aj said:

i dont have a GPS but cant you just switch one on if you are unsure
of your position to get a grid reference & keep it switched off the
rest of the time

Yes, you could, but that would be a waste considering all the other things
you can do with it.

At the very least, leave it switched on to record a track. Not only will it
give you statistics on exactly where you went, how far you walked, how long
it took, walking speeds and times at different points, but it can also act
as a useful breadcrumb trail. Let's say the mist came down or it got dark
and you needed to backtrack for some reason - far easier to follow the track
back (there is a "trackback" feature than have to faff about navigating the
usual way.

As for reading the grid ref and comparing it to a map, that's the hard way
to use a GPS. Just load up some well chosen waypoints beforehand and you'll
rarely ever need to read a grid ref, or even get out the map. You're
probably thinking of using the map for navigation and keeping the GPS in
your rucksack for emergencies. It's much easier to do it the other way
around, use the GPS for navigation and keep the map in your rucksack for
emergencies!

However, you do need some extra software and a lead to connect it to the PC
to get the best out of a GPS.

Paul

Peter Clinch said:

You can just switch on and get a reference, but you have to be in view
of at least 3 staellites. In the open this is more or less
guaranteed, at least within a short space of time, but in dense
forest or gorges and gullies etc., if you're out of line of sight of
satellites then you're snookered.
If the unit is left on it tends to keep a signal better than if it's
just turned on, which is worth noting in poor reception areas.

Indeed. I always find that mine keeps lock all the way to Sgwd Gwladys
(which is in a very deep forested valley), but once I lose lock there (which
I always do while I stop to take photos) I just can't get it to lock on
again.

Quoted message said:

Of course, this chews the batteries rather more.

True, but in these days of high power rechargeables, that's not really a
problem is it?

Quoted message said:

And of course navigation is more than just about knowing where you
are.

Quite. But knowing where you are is a good start!

BTW Pete, thanks for your advice back in the motivation thread some time
back (and everyone else who answered). I had planned to respond to yours
and others but I lost the messages before I got around to it.

As I recently heard someone say, "you don't get motivated to do something,
you do something then it motivates you! The motivation comes after doing
it!" So you were right after all. Clearly the pleasure you get from doing
something motivates you to do it again. You just have to do it before the
motivation fades.

Paul

Paul Saunders said:

True, but in these days of high power rechargeables, that's not really a
problem is it?

That very much depends on the discipline with which one monitors
and recharges batteries. While I'm certainly not arguing that's
impossible, or even difficult, the degree to which it happens is
very much dependent on individuals and their particular usage
patterns. I've seen quite a lot of high power recharageable bike
lights go flat, and not just mine!

Quoted message said:

Quite. But knowing where you are is a good start!

Absolutely, and a good piece of navigation means knowing where you
are, more or less, the whole time. If you already know you don't
need a GPS to tell you! That's much, much, much easier said than
done, of course...

Quoted message said:

BTW Pete, thanks for your advice back in the motivation thread some time
back (and everyone else who answered).

Glad to see you back motivated! :-)

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

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

Quoted message said:

aj said:

i dont have a GPS but cant you just switch one on if you are unsure
of your position to get a grid reference & keep it switched off the
rest of the time

Yes, you could, but that would be a waste considering all the other things
you can do with it.

At the very least, leave it switched on to record a track. Not only will
it give you statistics on exactly where you went, how far you walked, how
long it took, walking speeds and times at different points, but it can
also act as a useful breadcrumb trail. Let's say the mist came down or it
got dark and you needed to backtrack for some reason - far easier to
follow the track back (there is a "trackback" feature than have to faff
about navigating the usual way.

As for reading the grid ref and comparing it to a map, that's the hard way
to use a GPS. Just load up some well chosen waypoints beforehand and
you'll rarely ever need to read a grid ref, or even get out the map.
You're probably thinking of using the map for navigation and keeping the
GPS in your rucksack for emergencies. It's much easier to do it the other
way around, use the GPS for navigation and keep the map in your rucksack
for emergencies!

However, you do need some extra software and a lead to connect it to the
PC to get the best out of a GPS.

Paul

great advice thanks,now recommend a GPS unit please,there seem so be 2
around £100 etrex & Geko
which is better any idea,or is it wise to spend a bit more cash & get a
better unit?

In article <[email hidden]>, aj
<[email hidden]> writes

Quoted message said:

great advice thanks,now recommend a GPS unit please,there seem so be 2
around £100 etrex & Geko
which is better any idea,or is it wise to spend a bit more cash & get a
better unit?

As long as it is not the Geko 101 you are looking at either will be
fine. The 101 has no computer interface which means you cannot transfer
data but also means you cannot update the unit software to fix bugs etc.
Garmin supplies updates from their website so that users can update the
unit software for those with computer interfaces.

Take a trip to a shop that sells them and have a play with both if
possible to see which you prefer.

I have both a yellow eTrex and a Geko 201. I prefer the smaller and
lighter Geko. The battery life of the Geko is shorter but it takes AAAs
so it is trivial to carry a spare set. As I use rechargeable and rarely
bother to freshly charge them for a trip I nearly always carry spares
anyway so I benefit from the Gekos smaller / lighter batteries.

You should also beware that older yellow eTrex models had less capable
software than the Geko 201. At version 3 of the eTrex they became the
same. I'm not sure if any retailers will still have pre ver 3 eTrexes in
stock but it is worth checking that it is version 3 or later if you
decide to go for the eTrex. I would avoid version 2 units because of
their less capable software.

--

Dominic Sexton

Quoted message said:

As I use rechargeable and rarely
bother to freshly charge them for a trip I nearly always carry spares
anyway so I benefit from the Gekos smaller / lighter batteries.

You can get sleeve adapters that allow you to use AAA cells in place of
the AAs.

They weigh 2.5g each.

In article <[email hidden]>,
[email hidden] writes

Quoted message said:

Quoted message said:

As I use rechargeable and rarely
bother to freshly charge them for a trip I nearly always carry spares
anyway so I benefit from the Gekos smaller / lighter batteries.

You can get sleeve adapters that allow you to use AAA cells in place of
the AAs.

They weigh 2.5g each.

I could however I expect the AAA's won't last as long in the eTrex as
they do in the Geko.

Batteries are only part of the reason I prefer the Geko. It is smaller
and lighter itself, the button layout of the Geko is better for me and
the handlebar mount for it is better than that for of the eTrex series.
It is also less ugly!

--

Dominic Sexton