WAAS / EGNOS

[john_morris_uk]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

I agree - and you have to be moving to have the 'compass' reading make any sense. In fact I think calling it a compass on a GPS is wrong. Its not a compass at all, it tells you what bearing your 'track' is.

 

[fireball]

Compass on GPS

Some GPSs have a magnetic compass built in - and you can change the preferences for switching between the magnetic and GPS derived compass heading.

 

[john_morris_uk]

Re: Compass on GPS

Oh really?

Tell me which models exactly have a magnetic compass built in?

All the GPS's I have used use a built in 'variation map of the world' to give the ability to switch from magnetic to true figures....

 

[FlyingDutchman]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

Lemain,
You are right, I am a newbie in GPS.
Is not the COG easier to navigate with since the effects of wind and tide are already taken into account?

 

[Anonymous]

Re: Compass on GPS

[ QUOTE ]
Some GPSs have a magnetic compass built in - and you can change the preferences for switching between the magnetic and GPS derived compass heading.

[/ QUOTE ]I wouldn't thank you for such a facility - you would have to keep the GPS at a compass safe distance from all magnetic metal, oriented correctly, deviation checked (swung) and in any case I'd be confused about what I was actually looking at especially when things start to happen quickly and you really do need to know which way you are pointing (heading) and which way you are going (track)

David

 

[Anonymous]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

[ QUOTE ]
Is not the COG easier to navigate with since the effects of wind and tide are already taken into account?

[/ QUOTE ]If you are sailing in an area where the tidal streams are significant compared with the speed of your vessel you would find it difficult to manage with COG alone, I think.

If you are sailing in circumstances where a GPS is of use (as opposed to just being an intriguing toy) then you would benefit from an elementary course on basic navigation which will make the whole thing clear. It's very easy, actually, but not the sort of thing you can explain in a few forum messages. Someone else here might be in a better position to advise on that than I am.

David

 

[FlyingDutchman]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

I agree, I know little about navigation, but since we bought the boat in August last year without any navigation equipment (not even a compass) I want to have some elementary equipment for just in case. We mostly boat in channels or lakes in Holland, where navigation is not really an issue. However, we bought the boat in the northern part of the Netherlands an had to cross a part of the Ijssselmeer, the big inland lake. The weather was quite nasty and the visibility could have changed rapidly so this convinced me. that not having anything (like a compass, life vests etc) is not too smart, not to say foolish!

 

[Anonymous]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

That sounds sensible though a basic course would let you select the most suitable basic equipment and you would get more out of it. If nothing else, you would meet other boaty people on a course and it should be fun. Might also get you interested in going to sea - in an appropriate boat, of course. Having said that, if you are a fairly technical sort of person and get a grip on exactly what a GPS is, and what it is NOT, then your choice of the Garmin is a good one.

I find my old Magellan handheld useful sometimes when driving - I just insert the grid reference and it helps enormously when SWMBO says 'turn left' and the GPS says 'turn right' it is quite obvious which is to be trusted and which is to be obeyed - not always the same thing!

 

[FlyingDutchman]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

Thanks Lemain,
Yes I am a technical type of person so I am glad you say that the Garmin would be a good choice.
I think I will put it on my wishlist for my birthday for SWMBO. This should avoid future discussions on left or right?
Regards,
Jan

 

[Anonymous]

Re: Warning - excessive GPS accuracy may induce a false sense of security!

Jan, good luck with it and have fun!

 

[henkm]

Re: Compass on GPS

john_morris_uk wrote:
"Tell me which models exactly have a magnetic compass built in?.
All the GPS's I have used use a built in 'variation map of the world' to give the ability to switch from magnetic to true figures.... "

If one replaces the word 'magnetic' with 'electronic' the answer is:

Cobra GPS100
Garmin eTrex Summit
Garmin eTrex Vista
Garmin eTrex Vista C
Garmin eTrex Vista Europa
Garmin Geko 301
Garmin GPS MAP76CS
Garmin GPS MAP76S
Garmin GPSMAP 60CS
Lowrance iFinder
Lowrance iFinder Atlantis
Lowrance iFinder Express
Lowrance iFinder Pro
Lowrance iFinder Pro+
Magellan eXplorist 300
Magellan Meridian Platinum
Silva GPS Compass XL1000
Silva Multinavigator
Suunto X9

Example: http://www.garmin.com/products/etrexVistac/
Quote: 'Electronic compass for accurate bearing information while standing still'.

Note that this is different from the 'compass' screen on most other GPS-es, that does not give a (reliable) result when there is no speed.

Please correct me if I'm wrong or did not understand your point(!)

Henk



--
http://www.filo.nl/zeilen

 

[john_morris_uk]

Re: Compass on GPS

Well you learn something every day. My apologies for being so incredulous.

The next issue is how does the electronic compass work? If it is a fluxgate compass, unless it is a lot cleverer than many, it will rely on the instrument being held at the correct angle. I would be interested to see one in action to see whether it would work on a boat!

Still maintain that a magnetic compass is cheap and reliable.

Handheld GPS also traditionally eat batteries.

If I don't reply, its not because I'm ignoring you. I'm off to the boat show for the w/e. I will have a look at the handheld GPS's when I am there to see what's what.

Cheers

John

 

[Merman]

Re: Compass on GPS

[ QUOTE ]
Well you learn something every day. My apologies for being so incredulous.

The next issue is how does the electronic compass work? If it is a fluxgate compass, unless it is a lot cleverer than many, it will rely on the instrument being held at the correct angle. I would be interested to see one in action to see whether it would work on a boat!

Still maintain that a magnetic compass is cheap and reliable.

Handheld GPS also traditionally eat batteries.


Cheers

John

[/ QUOTE ]

John you do need to hold the compass in a gps level for it to work as you do with most fluxgate compasses. An electronic compass in a handheld gps such as my baby geko 301 that I use for hiking is really more a gimmick. I still use a traditional compass.

On the WAAS/EGNOS issue, it will make a huge difference to accuracy when it is switched on and working fully in Europe. I have used WAAS in the USA and it gave a superb accuracy. I do agree with someone earlier who stated switch off WAAS (It is EGNOS in Europe but the gps manufacturers still mark it as WAAS) until it is fully tested as it can put your fix even further out.

I love to read comment on the proper navigation versus electronic on these fora. I trained as a navigator on big boats and even though I know how to make passage traditionally, I use electronics at every oportunity. Time spent poring over a chart is time not spent keeping a proper lookout, and 90% of British sailors(made up stat) never go out of sight of land so pilotage is more important in my book.

Chris