IS a compass on a GPS a real necessity

[+bobpocha]

I recently picked up a Dakota 10 to try my hand geocaching.

It's a nice unit, but it does not have a compass..well,it does, but it only gives you a heading on your direction.

I have read that some users turn thier compasses off as it uses up alot of battery life.

 

I can upgrade to an Oregon 300 for about $60 more and was wondering if that would not be a better route?

I use a GPS for hunting and fishing and such, but now this "geocache" bug has got ahold of me...LOL

 

I want to buy a unit that I can use for a few years before having to upgrade again.

My last was the "old yellar" Etrex, still have it and still use it, but I am wanting to advance up...price is definately a key factor as well

[+Semper Questio]

I have a Garmin 60CSx and I thought I would use the compass a lot. Actually, I use it very seldom. Once in a while I will turn it on when I am trying to zero in on a cache, but I generally find it far too unreliable for regular use. When I need to get another GPSr, having the e-compass will NOT be a factor in my buying decision.

[+TotemLake]

There are those that will tell you it's a waste of money and those that will swear by it. You need to decide for yourself if having the sensor is going to be worth the extra bucks.

 

When a waypoint is selected as a GoTo, that is you're routing to it, the compass will give you a bearing of it in relationship to your location while standing still. This is in stark contrast to those that require you to walk at least 2MPH for 10-20 feet to get the compass rosette to point in the right direction in relationship to which way you're facing or using the sun/moon positions to get it right.

 

I use the compass to also give me a live triangulation as I'm walking towrds the cache in an indirect direction such as when on a trail and the trail is bending around a feature.

 

Ultimately, I won't buy a GPS without it. It's far easier to turn off what I have than to turn on what I don't have.

[NordicMan]

On my Vista Cx I don't see any appreciable difference in battery life if the compass is on or off.. I'm not sure where this compass "heavy battery drain" myth has ever come from, unless it IS a big drain on other brand/model GPSr's..

 

Personally I think the compass is invaluable! You can often be in an area like thick woods where it is nearly impossible to maintain a decen walking pace for long enough to allow the satellite compass to work..

 

And if you're trying to show someone else a bearing, do you really want them to jog alongside you & your GPSr to see an accurate pointer?

[+StarBrand]

Yup - some swear by the feature - others swear at it.

 

I fall in the latter camp - I find them to be near useless. Too much fussy calibration needed and too jerky to be of a lot of value. I use the electronic compass on my watch when I need one or just keep moving and let the normal gps compass get its bearings.

[+sduck]

For me it depends on the model of gps and the compass involved. I never once used the compass on my 60csx - it was too finicky. I left it turned off all the time. With my relatively new oregon 550t, it's got a 3 axis compass that seems to "just work", so I've been leaving it on, with no problems.

[+bobpocha]

OK..thanks so much.

I think I am gonna try out an Oregon 300 and see....can always exchange it anyway if it's not what I like, or want to spend the extra $$$'s on

[Braff-n-MandaRue]

Could always just carry a real compass.

[+Red90]

This is in stark contrast to those that require you to walk at least 2MPH for 10-20 feet to get the compass rosette to point in the right direction in relationship to which way you're facing or using the sun/moon positions to get it right.

 

All of the high sensitivity Garmin units I have owned only require you to move 5 feet at most to get the direction arrow to point correctly.

 

1000s of caches found. I never turn the compass on. Ever since they came out with the high sensitivity GPS units, it is not of any use.

[+Cardinal Red]

Could always just carry a real compass.

Carry 100 of them. It's not the same thing as a compass integrated into the GPS.

[+TotemLake]

This is in stark contrast to those that require you to walk at least 2MPH for 10-20 feet to get the compass rosette to point in the right direction in relationship to which way you're facing or using the sun/moon positions to get it right.

 

All of the high sensitivity Garmin units I have owned only require you to move 5 feet at most to get the direction arrow to point correctly.

 

1000s of caches found. I never turn the compass on. Ever since they came out with the high sensitivity GPS units, it is not of any use.

Good to know it takes less movement, but it still takes movement. I've been on trails 5 feet can be hazardous with Devil's Club on either side and a quick motion would send you sliding several feet in the muck downhill. It's nice to be able to point and click a waypoint and then let the compass point you in the right direction all in one tool. Of course then again, I'm also pretty big on aerial imagery.

Edited January 16, 2010 by TotemLake

[+ecanderson]

Could always just carry a real compass.

I don't think you appreciate the way we actually use the mag compass feature on our Garmin handhelds, or you probably wouldn't suggest that.

 

While constantly looking at the bearing to target on the Garmin and trying to orient a compass at the same time to get a heading while you're climbing sideways on a hill might sound like fun ... no, I think you understand why that isn't practical to suggest now, yes?

 

Seriously, if you haven't cached with a unit that includes a decent magnetic compass, you can't understand just how useful they can be, especially in avoiding the drunken bee dance.

 

I kept the compass on for all caching on my Summit HC, and that was one of those that had to be held fairly level to get a decent reading. My new Dakota 20 has the 3-axis compass, and has been dampened just a skosh, and on the whole works 100% better than the one on the Summit HC.

 

If you've never been able to just STOP along the way to a cache, get a decent heading off the mag compass, and move on according to the pointer, you don't know how nice that aspect of the feature can be.

 

If you've ever been up against the wall (literally), or under a bridge, or under tree cover, and had crap for an EPE reading as a result, you can't imagine how nice it is to back out from under the cover issue and take three visual bearings to the cache from 50' back or so from a clearing. Can't do that with the 'pseudo'compass that only tracks your motion.

 

The new 3-axis units are a lot smoother, very tolerant of position, and far less jumpy. For those that haven't seen one of these yet, you need to suspend any previous thoughts on the topic until you've tried one.

 

I see a LOT of "I hate hammers ... I keep hitting my thumb with them. They're clumsy." My advice: Learn to use the hammer properly, and you'll quit hurting yourself and find out how useful a tool it can be.

[+ecanderson]

1000s of caches found. I never turn the compass on. Ever since they came out with the high sensitivity GPS units, it is not of any use.

They cut down all the trees around Calgary again? Or did they plant more so that you can't back out to a clearing?

 

Seriously - YES, the high sensitivity units (and my Summit HC and Dakota 20 are BOTH high sensitivity units) make working under canopy easier, but the EPE can still stink if the trees/bridge/wall/building is a sufficient impediment that you need to back out a bit to get a clear reading. -159db sensitivity is great, but at least in the forests here in Colorado, not always quite enough.

 

2100+ found and not giving mine up! I know from experience how many times I've spent far less time as a result of its use.

Edited January 16, 2010 by ecanderson

[+DonB]

It may not be necessary but I personally wouldn't buy a GPS without it.

[+cestos73859]

bobpocha,

Gllad you started this thread. I have had the same question since my Out&Back has the same type of compass as the Dakota 10 - driven off the Satellite info. You have to be moving for it to work and I really think a true electronic compass would be better. The Endura Safari (big brother to my Out&Back) has a 3-axis compass which I am told is even better than a straight electronic compass but I wasn't sure if I would use the GPS enough to justify the extra cost.

 

As I use my GPS more for geocaching and for deer and duck hunting, I expect I will upgrade to theSafari and sell the Out&Back on Ebay.

[+BlueDeuce]

It may not be necessary but I personally wouldn't buy a GPS without it.

 

ayep.

Edited January 16, 2010 by BlueDeuce

[Rocketsteve]

I don't really use the compass on my Vista HCx when I'm caching. It does come in very handy during the pre-dawn hours during hunting season. In a couple of places where I hunt, the overhead tree cover is so thick that satellite signal reception is heavily impacted. I usually move into these areas 2 - 3 hours before sunrise to give myself plenty of time to get to my hunting spot and quietly set up. When it's a moonless night, combined with the heavy tree cover, it gets to be pitch black out there, and with only a red-light for illumination, it's quite hard to navigate without a compass. I usually move from the map screen to the compass screen repeatedly to make sure I'm on course, and since I don't have to hold my GPSr, my flashlight, and a REAL COMPASS too, there's no need to fumble around any more.

Edited January 16, 2010 by rocketsteve

[+keehotee]

Conveniently ignoring all of the above answers about accuracy, watch compasses, satellite reception, etc.

 

Yes - I use my GPS compass - because it's NICE to be able to turn around while moving OR stationery and always know what direction the cache is in.

[+StarBrand]

.....

I see a LOT of "I hate hammers ... I keep hitting my thumb with them. They're clumsy." My advice: Learn to use the hammer properly, and you'll quit hurting yourself and find out how useful a tool it can be.

I really hate it when somebody tries to diminish my opinion because they think I don't understand it or know how to "properly" use it.

 

Trust me - I know - and I still don't like them.

[+ecanderson]

Trust me - I know - and I still don't like them.

I refer to the new 3-axis variety. How much time have you had in the field with one of these? I'll trust when you tell.

 

The operation of the 3-axis units are like night and day vs. the old style, and deals with all of the complaints people tended to have in the past except calibration vs. battery voltage. For some reason, that seems inevitable in a Garmin design (sigh), but takes no more than a minute a couple of times through the course of a set of batteries.

[John E Cache]

Yup - some swear by the feature - others swear at it.

 

I fall in the latter camp - I find them to be near useless. Too much fussy calibration needed and too jerky to be of a lot of value. I use the electronic compass on my watch when I need one or just keep moving and let the normal gps compass get its bearings.

If you are constantly calibrating because it is "jerky", you have no clue. The OP has to determine why some people like the compass and some people don't.

[+ecanderson]

If you are constantly calibrating because it is "jerky", you have no clue. The OP has to determine why some people like the compass and some people don't.

Yes - general dislike or like doesn't help the OP at all. You can bet he's hoping for specifics that will guide his decision.

 

What is interesting, though, is the representation of two very vocal camps. One wouldn't buy a unit without a mag compass, and others hate them. These two groups either 1) have very different terrain experiences while caching, and the existence of more than one use model is swaying opinions in the direction of their local conditions, or 2) they are have used or are using the compass feature differently, and due to that, coming up with different results, 3) some folks have had some bad equipment to work with that has colored their opinions.

 

I'd be interested to hear of more explanations for the extreme dichotomy of opinion, but I'm guessing that those above cover most of the ground. Understanding the circumstances that cause this might go a long ways towards answering the OP's real question.

Edited January 16, 2010 by ecanderson

[+StarBrand]

Yup - some swear by the feature - others swear at it.

 

I fall in the latter camp - I find them to be near useless. Too much fussy calibration needed and too jerky to be of a lot of value. I use the electronic compass on my watch when I need one or just keep moving and let the normal gps compass get its bearings.

If you are constantly calibrating because it is "jerky", you have no clue. The OP has to determine why some people like the compass and some people don't.

I constantly calibrate it because I change the batteries and/or it has been in the car or its pointing off to the setting sun and telling me North.

 

Its Jerky because it varies several degrees back and forth - even held level and holding still. I have tried it on several brands and models. Always the same.

 

No thanks - I don't need it - way too unreliable, way to jerky, way too tempermental.

 

Yeesh guys - I get it - you like and swear by it - and have stated your opinion of it.

 

So have I - have a little basic respect that I know how it works, know how to use it - and yet I still don't care for it.

[+StarBrand]

If you are constantly calibrating because it is "jerky", you have no clue. The OP has to determine why some people like the compass and some people don't.

Yes - general dislike or like doesn't help the OP at all. You can bet he's hoping for specifics that will guide his decision.

 

What is interesting, though, is the representation of two very vocal camps. One wouldn't buy a unit without a mag compass, and others hate them. These two groups either 1) have very different terrain experiences while caching, and the existence of more than one use model is swaying opinions in the direction of their local conditions, or 2) they are have used or are using the compass feature differently, and due to that, coming up with different results, 3) some folks have had some bad equipment to work with that has colored their opinions.

 

I'd be interested to hear of more explanations for the extreme dichotomy of opinion, but I'm guessing that those above cover most of the ground. Understanding the circumstances that cause this might go a long ways towards answering the OP's real question.

Your basic premise here is that over the "proper" terrain and circumstances AND if the user knew what they were doing AND they had good a functioning GPS with a 3D compass that 100% of cachers would enjoy using the electronic compass.

 

Nope - not true. I am glad you like yours - i've turned mine off and intend to leave it that way.

 

The OP asked if a compass was a necessity for Geocaching. It isn't. Opinions vary from there.

[+ecanderson]

The OP asked if a compass was a necessity for Geocaching. It isn't. Opinions vary from there.

 

NO - a compass is NOT a necessity. Neither are PQs, EPE numbers of the face of the GPS, or any number of other features. People find good uses for each of them. A GPSr isn't a necessity for geocaching, either. Before I sent a friend in Florida my old eTrex unit, he and his son were finding them using Google Earth. Each person takes his selection from the available tools to make his caching experience either more efficient or more enjoyable or both.

 

But you still haven't answered my earlier question -- have you had any experience with the new 3-axis units? Or were you too put off by your prior experiences to bother with one?

[Grasscatcher]

This whole thread could have been eliminated by a one word answer post as the second post...............NO

 

The reason for the multiple opinion camps is that there are WAAAAY more GPS users out there that don't really have a clue how the GPS compass really works. They THINK they do , but, by their comments, it's obvious that they don't. Guess what....the pointer isn't the compass......

 

I've got a Trimble (no compass), a 76CS, a 76CSx, and a Oregon 550.

Note that some are 2 axis and the Oregon is a 3 axis. All the compasses work perfectly, no hanging, not jumpy,etc.and when used correctly are as accurate as a normal magnetic handheld compass .

 

All that being said, I'm in Starbrand's camp......I leave them turned off in normal GPS use. When I need a compass, I turn it on, calibrate and read....then off again.

 

With the 60/76 series, it's physically impossible to use the compass and have the GPS operate the most accurately at the same time anyway. Antenna works most accurately vertical and the compass only operates horizontally.

Different strokes for different folks.......

[+StarBrand]

...

-- have you had any experience with the new 3-axis units? Or were you too put off by your prior experiences to bother with one?

Tried them. Same wonkiness.

 

Opinion Remains.

[+ecanderson]

 

All that being said, I'm in Starbrand's camp......I leave them turned off in normal GPS use. When I need a compass, I turn it on, calibrate and read....then off again.

It's my impression that Starbrand doesn't even have any use for them to that degree. You don't use your GPS for navigation to geocaches much, do you? I get the impression that you use yours more for track building and 'outback' navigation, and don't have reason to use it for triangulation of a specific point very often.

[+ecanderson]

...

-- have you had any experience with the new 3-axis units? Or were you too put off by your prior experiences to bother with one?

Tried them. Same wonkiness.

Should have returned it as defective. In operation, they don't even resemble the same tool apart from the visual on the face of the GPS. When I got my Dakota 20, I started doing side-by-sides with my eTrex Summit HC. Light night and day in this particular respect.

[+StarBrand]

....

You don't use your GPS for navigation to geocaches much, do you? I get the impression that you use yours more for track building and 'outback' navigation, and don't have reason to use it for triangulation of a specific point very often.

I own 10 different models. Have reviewed many others.

 

The primary use is for Geocaching.

 

I haven't the foggiest clue what you are talking about with triangulation as it relates to your average tradtional cache..

[+StarBrand]

...

-- have you had any experience with the new 3-axis units? Or were you too put off by your prior experiences to bother with one?

Tried them. Same wonkiness.

Should have returned it as defective. In operation, they don't even resemble the same tool apart from the visual on the face of the GPS. When I got my Dakota 20, I started doing side-by-sides with my eTrex Summit HC. Light night and day in this particular respect.

I'll try and explain this one more time.

 

I personally do not care for the fact they need regular calibration. I do not care for the fact they do not remain steady but instead swing a few degrees back and forth.

 

2D, 3D - makes no difference - I perfer the electronic compass on my watch. No calibrations needed - it just works. Never let me down or gave a false reading due to new batteries or car use yet.

 

YMMV.

[+ecanderson]

I haven't the foggiest clue what you are talking about with triangulation as it relates to your average tradtional cache..

I think I made that pretty clear either here or in another similar thread that is currently running on this page. It's not necessary for every cache - VERY helpful for some. If by "average", you mean one situated under more or less ideal conditions, no need at all. If you've never had to back out of tree cover or a away from a bridge or a building or a canyon wall to shoot a couple of bearings to get a better idea of the location when your EPE was on the order of 60', then I can understand why you never have had a use for one.

 

I'd rather have a better idea of where the cache is a bit more quickly and spend a bit less time wandering in circles under circumstances like those. While the CO may have the time during a placement to take a dozen averaged readings under those conditions, I usually don't want to spend quite that amount of time waiting for the GPS to settle to usable reading... especially my new Dakota 20 -- which while it has a vastly improved compass, takes FAR longer to settle than my old Summit HC ever did, even under good conditions.

 

Anyway, I've been at too many sites out here in Colorado where you can't just "walk in" to a cache using the GPS because as you approach, the accuracy goes all to hell. For easy caches, you could practically do it by looking at the raw lat/long numbers. I'm talking about those circumstances where the easy way just isn't getting it. Backing off and shooting a couple of eyeball lines from a couple of angles has proved very useful when used to full advantage WHEN it's needed. That goes back to the "use model" or whatever I called it before. If a person doesn't cache in situations like that, they could probably do as well if a pair of lat/long numbers were the whole user interface for the GPS... just keep walking until you get the ones on the cache page.

[Forkeye]

Could always just carry a real compass.

Carry 100 of them. It's not the same thing as a compass integrated into the GPS.

VERY TRUE...a real compass can be trusted.....when things dont seem right with a Garmin compass ,there usually not!I almost always check my Garmin against my real compass.That Garmin is sometimes spinnier than a **** house rat!

[+Red90]

They cut down all the trees around Calgary again? Or did they plant more so that you can't back out to a clearing?

 

Seriously - YES, the high sensitivity units (and my Summit HC and Dakota 20 are BOTH high sensitivity units) make working under canopy easier, but the EPE can still stink if the trees/bridge/wall/building is a sufficient impediment that you need to back out a bit to get a clear reading. -159db sensitivity is great, but at least in the forests here in Colorado, not always quite enough.

 

I see what you are getting at, but the compass is useless in low EPE situation when finding a cache. Because you are so close, the reported position jumps around and the compass does the dance of life.

 

I have tried with and without compass and finding a cache is always faster without.

[+ecanderson]

They cut down all the trees around Calgary again? Or did they plant more so that you can't back out to a clearing?

 

Seriously - YES, the high sensitivity units (and my Summit HC and Dakota 20 are BOTH high sensitivity units) make working under canopy easier, but the EPE can still stink if the trees/bridge/wall/building is a sufficient impediment that you need to back out a bit to get a clear reading. -159db sensitivity is great, but at least in the forests here in Colorado, not always quite enough.

 

I see what you are getting at, but the compass is useless in low EPE situation when finding a cache. Because you are so close, the reported position jumps around and the compass does the dance of life.

 

I have tried with and without compass and finding a cache is always faster without.

YES! I fully agree. Exactly! IF, that is, you are standing in a low EPE spot! The point is to get out of that spot and then triangulate!

 

Using the mag compass as a pointer to the cache direction while you are standing in a low EPE situation IS darned near useless apart from knowing which way is north, which isn't what you want to know. Heck, using the GPS at all in bad EPE is nearly impossible. In both cases, the GPS doesn't know with any accuracy where you are, so the pointer on the compass cannot accurately direct you to where you need to be. And as you note, that's especially true as you get closer to the target under bad EPE conditions... the GPS' idea of the target location wanders all over the place relative to where you are standing.

 

It is under those circumstances that I will try to back OUT of the immediate area of the cache and into an area (or areas) nearby where there's at least a little bit more clear sky with a decent EPE and shoot one or more bearings from there. If I can back out into some clear space, especially from two positions, I can draw lines of sight and get a general idea of where they intersect.

 

I'm telling you - if you haven't had a reason to use this technique, or just haven't tried it yet, I can fully understand your skepticism.

 

All of this presumes, of course, that the CO takes the additional time necessary to get the averaged readings necessary to produce a decent set of coordinates in the first place. If it ain't where he said it is, all bets are off, and no feature on your GPS is going to make it any easier.

[+Red90]

that is, you are standing in a low EPE spot! The point is to get out of that spot and then triangulate!

 

If you can walk to a low EPE spot, the GPS pointer will show you where the cache is located. There is no need to stop and turn on a compass.

 

While you stop and do projections, I'll already be at the correct zero looking for the cache. I do the projections while walking to the cache. No need to slow down or stop to triangulate.

[Braff-n-MandaRue]

Could always just carry a real compass.

I don't think you appreciate the way we actually use the mag compass feature on our Garmin handhelds, or you probably wouldn't suggest that.

 

While constantly looking at the bearing to target on the Garmin and trying to orient a compass at the same time to get a heading while you're climbing sideways on a hill might sound like fun ... no, I think you understand why that isn't practical to suggest now, yes?

 

No, I've had several GPS units with the built in magnetic compass, didn't like them.

 

I've never had a problem with getting a bearing off a GPS then finding it on my compass. Hillside or not. It takes like five seconds to do. To me, it's very practical, and I don't have to worry about the batteries in my compass dieing or recalibrating it. It's there, and it's ready.

 

I'm not going into any explanation of GPS models used, 2-axis, or 3-axis. It's not important, either way, I just don't like them. You like them, I don't. That's a good enough explanation for me.

[+ecanderson]

that is, you are standing in a low EPE spot! The point is to get out of that spot and then triangulate!

 

If you can walk to a low EPE spot, the GPS pointer will show you where the cache is located. There is no need to stop and turn on a compass.

 

While you stop and do projections, I'll already be at the correct zero looking for the cache. I do the projections while walking to the cache. No need to slow down or stop to triangulate.

Are you talking about the little blue arrow on the map display when you refer to a "pointer"? How the heck do you shoot a bearing to the cache (before re-entering the low EPE area) without staying on the move?

 

I don't stop to turn on the compass -- battery life is good enough with it enabled that I leave it enabled when I think it might be useful.

 

So how are you using the blue map arrow, if that's what it is, to move in to the cache? You must still be projecting a point in your mind's eye, since you can't trust the blue arrow once you start to move back into the bad EPE area. It's an especially big problem when the terrain won't let you just walk in a straight line. The mountains here have some major outcroppings of rock that often prevent that.

 

When you are leaving the bad EPE area for a better one, are you trying to walk 180 degrees away from the cache on the map, then trying to do a 180 and walk back towards it, or ???

[+Red90]

You look at where the arrow is pointing as you walk towards or by ground zero while in the low EPE area. It is simple. No problems triangulating to within a meter. You can then put the GPS away...

[Grasscatcher]

Here is a perfect example of comments in my earlier post.....

 

ecanderson, why do you keep refering to the pointer like that is the compass? You can turn the compass off (or not even have one) and, if you are navigating to a set of coordinates, you STILL have the pointer.

 

The pointer is pointing to a set of coordinates, a spot, the cache location. It could not give a hoot which compass direction that is. The bearing pointer is what you are using to "triangulate" with., not the compass.

Guaranteed, if you turn the compass off, you'll find the cache quicker, with less confusion about what your unit is "telling" you.

 

3,4,7 different people could be coming to the same location from all different directions, and all their "pointers"would be directing them to the same spot. ...and some of them likely would not even have a compass.

 

Also, try using UTM coordinates instead of Lat/Lon. As Red 90 said, you can triangulate without ever stopping, essentially simulating those multiple people. Bingo! there it is. No dancing compass , no problems.

Edited January 17, 2010 by Grasscatcher

[+ecanderson]

Here is a perfect example of comments in my earlier post.....

 

ecanderson, why do you keep refering to the pointer like that is the compass? You can turn the compass off (or not even have one) and, if you are navigating to a set of coordinates, you STILL have the pointer.

Only means something if you're moving. When you are stationary or moving slowly (through brush or in a boulder field) and on the compass page, the only reason the pointer can point TO the cache is the information provided by 1) the GPS (your current position and that of the cache) and 2) the availability of the magnetic compass. Without #2, the GPS has ZERO idea of your orientation and the orientation of the thing in your hand vs. the target, and is completely unable to provide the needed information. You'd get more from a physical compass and a calculator (i.e., what's inside my GPS!). At a minimum, you'd need a separate compass so you could use the bearing information to figure out the direction of the cache.

 

I believe you and I are either talking about entirely different "pointers" (the device has two - one small blue one and one large red one) that are accessed from entirely different pages, or confusing the heck out of those folks who are trying to follow what the red pointer does. For those that haven't picked up on this...

 

The blue one shows up on the map page. That one hasn't been the focus of my posts, but if you have a GPS that does not include a magnetic sensor, you might as well use that as the red one -- the information is coming from the same source -- whatever GPS readings you can get by staying in motion that provide some clue as to your track direction vs the static position of the target.

 

The red one appears on the "compass" page. How this pointer operates is different if you do/don't have a magnetic sensor (called an "electronic compass" in the specs - the manufacturer's choice of words, NOT mine). That's true of the little blue one, too, but it's usually smaller and not as easy to read.

 

If the GPS does not employ a mag sensor, unless you are moving and the GPS is trying to sense your bearing based upon that movement to provide a bearing to the cache, the red arrow provides no useful information unless you're carrying additional hardware with you. If you own a GPS without a magnetic compass, you must be moving to give the GPS some idea of your direction of travel, the GPS will ASSUME that you are pointing the GPS directly in front of you, and it will then attempt to move the red pointer at some angle against what it believes to be your current direction of travel to give some idea of the course correction needed for a direct line to the cache. It is not possible to stop and shoot a bearing toward the cache with the red pointer under those circumstances. It also requires that you keep the GPS pointed directly in front of you. Again, the unit has NO idea of the devices actual (physical) orientation vs. north, the cache, or anything else. It's not really a compass at that point - just a way of showing what the proper bearing would be if you had a real compass to figure out where that was. The pointer is pointless. You just need degrees shown on the face of the unit. That the arrow continues to be displayed under those circumstances is, in my opinion, not a good design for the user interface - it confuses people.

 

A GPS with a magnetic sensor providing data to the compass page is capable of producing a useful result while you are in a stationary position or moving slowly because it has knowledge of the current orientation of the GPS (the direction in which it is currently being held in your hand vs. north). The angular resolution of the magnetic sensor employed in these units is higher than can be produced by using the delta of the GPS coordinate data when moving only a short distance. In fact, if you don't move fast enough or far enough, your motion appears as nothing more than a little GPS coordinate drift (a wandering pointer) if no mag sensor is being used.

 

The operation of the red pointer on the "compass" page is therefore quite different between units with/without an integrated magnetic compass chip. It provides a more useful result when a GPS incorporates the magnetic sensor and makes use of that data to drive the position of the red arrow.

 

A word to those not 100% familiar with Garmin's implementation of the mag sensor feature: all of the units I've seen so far include an option to utilize the magnetic sensor data either full time, or only if your speed drops below a specific rate for some period of time, to provide the red pointer's position. This is a tacit acknowledgment that unless you are moving, and at some reasonable speed so that the coordinate data provides an accurate bearing on an ongoing basis, the quality of the red pointer's information is seriously degraded. Most of us are happy enough to leave them at their 5mph for 5 second default or whatever the unit provides from the factory. Since good GPS bearing data can be had at speed, the battery savings from switching off the magnetic sensing chip when moving along at speed adds a bit to battery life... we assume that's why the threshold was made available.

Edited January 17, 2010 by ecanderson

[+agentmancuso]

On my Vista Cx I don't see any appreciable difference in battery life if the compass is on or off.. I'm not sure where this compass "heavy battery drain" myth has ever come from, unless it IS a big drain on other brand/model GPSr's..

 

I have the same model and have had exactly the same experience - it doesn't seem to reduce battery life by any measurable amount.

[+ecanderson]

On my Vista Cx I don't see any appreciable difference in battery life if the compass is on or off.. I'm not sure where this compass "heavy battery drain" myth has ever come from, unless it IS a big drain on other brand/model GPSr's..

 

I have the same model and have had exactly the same experience - it doesn't seem to reduce battery life by any measurable amount.

I read a pretty nice piece on this recently in another thread here. I believe the figures after a few tests revealed no more than a 5% differential for any of the (Garmin) units he tested. The issue of mag compass, WAAS and backlight to max the battery life has been played out here a few times. I'd only bother turning mine off if I was really concerned I was going to run out of juice for some reason, and needed the absolute maximum longevity out of the currently installed set. As frequently as I swap 'em, it never matters to me.

[GlfWrVt]

I just checked my 60CSx mag compass with my suunto M-2 mag compass. The 60CSx is 10 - 15 degrees off all the time. This is taking into account declination.

 

-Mark.

[+ecanderson]

I just checked my 60CSx mag compass with my suunto M-2 mag compass. The 60CSx is 10 - 15 degrees off all the time. This is taking into account declination.

 

-Mark.

Was that right after you ran a calibration on it? Was the error always in one direction (- or + degrees)?