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Discussion Starter · #1 ·
I'm looking at GPS units, and in the price range I am considering (about $150-200, yes, I know that is the low end) I find I can get either a map readout with no compass, or a compass with no map readout. I can see advantages to both/either. Is one more important/useful than the other?

I also notice that the units that have color screens say something like "daylight readable color screen." Are the b & w screens all that difficult to see in the sun? Or is the marketing department just trying to get you to spend the $ to upgrade to a color screen?

Any other features to consider?

Oh yes, I would use it mostly for cycling and hiking, my wife things she might like to get in to geocaching, if all of that makes any difference...

Thanks in advance.
 

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slow up slow down said:
I'm looking at GPS units, and in the price range I am considering (about $150-200, yes, I know that is the low end) I find I can get either a map readout with no compass, or a compass with no map readout. I can see advantages to both/either. Is one more important/useful than the other?

I also notice that the units that have color screens say something like "daylight readable color screen." Are the b & w screens all that difficult to see in the sun? Or is the marketing department just trying to get you to spend the $ to upgrade to a color screen?

Any other features to consider?

Oh yes, I would use it mostly for cycling and hiking, my wife things she might like to get in to geocaching, if all of that makes any difference...

Thanks in advance.
If you want to save money, don't bother with the map, as it's of low utility unless you buy the map software, for which you'll likely have to pay another $80 to get the proprietary map software for your unit. That said, a map is still a great feature for navigation in strange areas if you can afford it - even for the road on the way to the trail. But then you need to buy two software maps- one Topo and one Road (which is what I do and swap them in software on the GPS).

The compass screen will work as long as you're moving on all GPS units with that screen. The extra magnetic compass is good for pointing when stopped, but not that essential - unless Geocaching. When Geocaching, the compass pointing the way and distance to the cache was a BIG help. A GPS without that feature was essentially useless by comparison.

B&W displays are generally great in the sun on most units, and have higher resolution. But it used to be that color screens were practically invisible in bright sun. But the new color screens (like on my Garmin) are super readable in bright sun now. Color is a very nice enhancement, like having more pixels if you can afford it. But color is most useful on maps, which you may not get.

For me, the most useful feature is the barometric altimeter. For a lot of steep climbing, knowing the altitude is more important than distance sometimes in locating your position on a map (altitude helps you a lot by placing you on the right contour on the map). And altitude is more important for me than distance in how much effort is left to reach a peak on a ride. With an altimeter, you can also get better ride profiles later at home. A GPS without a barometer can give you altitude with enough satellites, but it's nowhere near as accurate - maybe only +/-100' or so versus just a few feet error with a barometric altimeter calibrated at the beginning of the ride.
 

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Big Larry said it well. I use a Garmin 76 (for boating, hiking, some geocaching ) and never really used the map feature. I carried the appropriate map/chart and used the lat/long as well as the compass to find my way...like B.L. said, you have to be moving to really use the compass which could be tricky on a mtb....send me a pm if you have any more ques...

Also, any new models of GPS would be better than older models. The older models tended to eat batteries like crazy...

Capt Stu
 

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I bought my first GPS last year and was originally looking at a top of the line Garmin. However, by the time I'd have got the Topo and Blue Water charts I would have been up towards a thousand dollars. I tried a different store and their first recommendation was to go with Lowrance for their supposed better reception under tree cover. At this point, I decided to buy the cheapest Lowrance to see how the reception was and decide if I was really going to be using a GPS unit. I spent a mere $100 on a Go2.

My reason for purchase was for a sea kayaking trip so I was looking for something fairly compact with a degree of waterproofness. The Go2 fit the bill and performed flawlessly despite being dropped in sea water on the second day! I now use it regularly for mtb rides and hikes. I actually just slip it in my camelback and forget about it. It draws a line wherever you go, and you can refer to it if you need to backtrack or are lost. Wet tree cover definitely causes more breaks in the signal, though.

Another bonus of this unit are that it comes with basic mapping included. I was surprised to find that the remote islands that I kayaked in were included, but they were somewhat triangulated in shape. You'll find that roads are drawn through the edge of lakes etc. I consider mapping to be a very important feature with modern GPSs. If lost, you'll know where the closest road or lake etc. is situated.

The Go2 also has incredible battery life, being a simple unit. I can get 48 hours out of it in 'easy' mode on two AA batteries, which is amazing. Its main drawback is that you can't interface with your computer to download your trips. I'll certainly be upgrading at some point, but see no reason to yet.

Finally, I've done a couple of geocache routes and found no need for an electronic compass. You just walk in a general direction and it becomes obvious if you're heading on the desired bearing. It's fun. My wife and I have just designed and put up a new geocache.
 

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I picked up the Garmin Etrex Legend and the handlebar mount from Amazon for $150 (shipping included). I like the map feature. I use Topofusion and trail maps to kind of trace out routes I'd like to try, load them into the etrex, and off I go. You can also find some people on MTBR who ride with gps and are willing to share their track files.
 

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Garmin eTrex Summit

It's important to get the right GPS unit as the display, features, button layout, form factor, and software are optimized for each intended use, such as automotive with voice routing, boating, geocaching, or hiking/biking and work poorly for other uses.

I'm very familiar with the Garmin line, and own a few of their products. For instance, they have (expensive) Edge cycle computers that are not much more than a fancy bike odometer and performance monitor that are good for training but not the best for MTB in my opinion. (I have a detailed comparison on another thread.) They have Foretrex and Forerunner that fit on the arm and give basic data and store tracks. For hiking, they also have the bigger GPSMAP line. My next unit will likely be a bigger $400 GPSMAP60CSx with removable memory, big display, and specific geocaching screens.

But the perfect line for biking/hiking is the eTrex line, in terms of size, display, software features. For cost sake, I don't include the color screen units, as the high resolution B&W works fine for mapping, if desired. Here's the relevant units of interest in order of price, which are the lowest I got from Yahoo Shopping:

eTrex (alone): $85 Stores 500 Waypoints, 20 Routes, 10,000 track points, Low Res display
eTrex Summit: $160 Stores 500 Waypoints, 20 Routes, 10,000 track points, Low Res display, Compass and Altimeter
eTrex Legend: $120 Stores 500 Waypoints, 20 Routes, 10,000 track points, High Res display, 8 MB memory
eTrex Vista: $182 Stores 1000 Waypoints, 20 Routes, 10,000 track points, High Res display, Compass and Altimeter, 24 MB Memory

Edit: New eTrex line came out. Here's some of the features for better color models
eTrex Venture Cx $200 In the past it was like the Legend but less memory for slightly less $. Still no sensors, but can do color maps with expandable memory.
eTrex Vista Cx: $300 The best of the eTrex line. It has sensors, expandable memory, high resolution color maps. It can do everything same as the GPSMAP60CSx, but in a smaller rugged package. Unfortunately, like all the eTrex line, it's missing the more sensitive SiRF III receiver. :(

The basic eTrex at $85 will serve you well.
For MTB, the barometric altimeter is a good feature.
For Geocaching, the electronic compass is a good feature
You get them together with either the Summit or Vista, but at a cost seen above.

If you don't want a map, the low resolution screen of the first two will be fine. The memory is only needed for maps and fits with the higher resolution screen on the latter two units. Note Vista has map ability and other upgrades for a mere $20 more than the Summit. I've been using the Vista for 3 years now myself as a favorite GPS for MTB.

The Summit has about double the battery life of the Vista, 22 hours versus 12 hours. (You generally don't need the compass on during MTB, which reduces Summit battery life to 13 hours - about that of the Visa.) In any case, you want to buy some rechargeable AA batteries (get 4 so you have extra for swapping). All these units will last an epic ride if started fully charged.

You may want to look at the wrist mounted units, the Foretrex and Forerunner, none of which have altimeter or compass. But the Forerunner can't store routes, a critical flaw for navigating. The Foretrex is better and stores routes, but costs more than the eTrex units without a compass or barometer.

Don't worry about the ruggedness of the eTrex. I've had mine mounted on the handlebars for years through the toughest of rock gardens and many endos and crashes. It's very rugged with rubberized sides and waterproofed, built to take continous 8 G forces. I've dropped it down a a bunch of rocks once by accident, and left it on the roof of my car while it bounced down the paved highway (twice). On the other hand, my frame has broken twice, and many other parts of my bike needed replacing. The eTrex GPS is the strongest part on my bike.

Also, all the Garmin lines can interface with Motion Based web software that is superb. You can plot your tracks out on 3D maps with the background being topo, satellite, or many other options. It will plot out your ride altitude profile, and so on.
 

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BigLarry said:
My next unit will likely be a bigger $400 GPSMAP60CSx with removable memory, big display, and specific geocaching screens.
I got a 60CSx to replace my VistaC. The 60CSx is much faster, much more accurate and is a significant improvement. I use it for downhill skiing, mountain biking, geocaching, hiking and even driving (when going somewhere I'm not familiar with).
 

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I just replaced my etrex summit with a 60csx, my advice is save up a couple of more weeks and get the 60csx, better reception and faster, better screen, removable memory(I loaded the east coast topo & North america streets and I have lots of room left. It is a little bigger, but I keep it in my cell phone pocket strapped to my camelback harness, it also has a handlebar mount. as far as screen viewability its incredible, I bought the car kit, mounted it on my dashboard in a convertible and could read it at all times, even with the sun behind me and it gives turn by turn directions . It can be found online for $400. If you really want an etrex summit I'll sell mine with the bike mounts $75.00
 

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Discussion Starter · #10 ·
Thanks!

Thanks everyone - and esp. Big Larry - for all of your great advice. I hadn't thought so much about the altimeter.

How accurate are they, these days? When I was living up in Oregon I had an altimeter on my bike computer, but I found the weather fronts blowing in and out of that part of the country, the altimeter was not very useful. "uh....I either climbed a lot, or expect rain soon."

That was several years ago, though, and I live in an area of pretty stable weather now. Is the altimeter fairly accurate these days?
 

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Jdub said:
I got a 60CSx to replace my VistaC. The 60CSx is much faster, much more accurate and is a significant improvement. I use it for downhill skiing, mountain biking, geocaching, hiking and even driving (when going somewhere I'm not familiar with).
Jdub:

I am weighing the cost/benefit of the 60 CSx vs the Etrex series. How much bigger is the 60CSx vs the Etrex and is it OK for driving?

Would you mount it on your handlebars or is it too big for that?

Thanks in advance
 

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Barometric Altimeter Issues

slow up slow down said:
Thanks everyone - and esp. Big Larry - for all of your great advice. I hadn't thought so much about the altimeter.

How accurate are they, these days? When I was living up in Oregon I had an altimeter on my bike computer, but I found the weather fronts blowing in and out of that part of the country, the altimeter was not very useful. "uh....I either climbed a lot, or expect rain soon."

That was several years ago, though, and I live in an area of pretty stable weather now. Is the altimeter fairly accurate these days?
The resolution of the Garmin barometric altimeter is 1 foot. I can walk up a couple stairs and see the difference in altitude. This resolution helps get a more accurate climb. Some altimeters with only a 5' resolution will miss some of the smaller climbs and give a few percent lower total climb number than mine. The accuracy depends on the calibration when first starting the ride. I can usually figure out the starting elevation from the Garmin Topo map on my GPS, or other maps around. If nothing else, I plug in the satellite number, but I usually find something better since that's often over 100' off.

Nothing's perfect. I indeed get a gradual drift due to weather with a lower or higher pressure front moving in. On a typical ride of a few hours, I typically only see 30' drift error between start and finish (at the same point and altitude). But I did have a long ride once when a big weather front came in and had nearly a 200' change - that was the worst and rare. The next worst I ever saw was under 100' error, which is the error you'll get with the satellite based altitude up and down all along your ride, not just a gradual drift.
 

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Juhs22 said:
Jdub:

I am weighing the cost/benefit of the 60 CSx vs the Etrex series. How much bigger is the 60CSx vs the Etrex and is it OK for driving?

Would you mount it on your handlebars or is it too big for that?

Thanks in advance
The 60CSx would probably work for driving. But I got a portable little Garmin Quest for the car and walking around the city. It's got a speaker with voice prompts built into the charger plug, and many other nice features specific for car navigation.

The 60CSx is great for Geocaching and even has a special screen for that purpose, I've read.

The 60CSx is about 1.3X (30%) bigger than the eTrex, not that much. It has a handlebar mount and will work there. I've seen it on the handlebars of a friend's bike and wanted one too. Actually, you want it on the handlebars so you could use the better map display which is the whole point.

The eTrex is easier to fit with other gear on the bars, and barely noticable relative to other bike computers. For some reason, that 30% increase in size makes the 60 CSx look almost like you're carrying a big PDA or small notebook computer along. Nevertheless, I do like the nice big color display and want the larger unit on my next upgrade. There's many other nice things about the 60 CSx too (better reception, replacable memory, ...) It's a Man's GPS.

From Garmin's Product Comparison page:

GPSMAP 60CSz
Unit: 6.1 x 2.4 x 1.3 inches
Color Display: 2.2 x 1.5 inches
Color Display Pixels: 240 x 160 (color)

eTrex
Unit: 4.4 x 2.0 x 1.2 inches
Display: 2.1 x 1.1 inches (High Res B&W)
Display Pixels: 288 x 160 (High Res B&W)
Color Display: 1.7 x 1.3
Color Display Pixels: 220 x 176
 

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Good Advice

BigLarry said:
The extra magnetic compass is good for pointing when stopped, but not that essential - unless Geocaching. A GPS without that feature was essentially useless by comparison.

A GPS without a barometer can give you altitude with enough satellites, but it's nowhere near as accurate - maybe only +/-100' or so versus just a few feet error with a barometric altimeter calibrated at the beginning of the ride.
Big Larry offers some great advice. From all his points, I'd only challenge two.

1. I manage to geocache without a magnetic compass without much problem. I'll admit it would be nice-to-have, though. you could buy a separate compass, though.

2. I'm perfectly happy without a barometric altimeter and find that the GPS altitude reading is usually very close to accurate (+/- 5 meters). It also doesn't need calibrating, which the barometric one always will.
 

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Juhs22 said:
Jdub:

I am weighing the cost/benefit of the 60 CSx vs the Etrex series. How much bigger is the 60CSx vs the Etrex and is it OK for driving?

Would you mount it on your handlebars or is it too big for that?

Thanks in advance
Big Larry pretty much detailed it out.

The 60CSx is noticeably bigger than the Vista I had before, in fact my wife even made a comment to that fact. I did buy the handlebar mount, but I only use the handlebar mount when I'm doing geocache stuff so I can navigate as I ride along.

Its OK for driving, but not great by any stretch. I wouldn't want to use it for driving heavily, but every now and again it works just fine.

Overall its a large jump in overall satisfaction from the Vista C to the 60CSx in just about every category.
 

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Maybe

SwissBuster said:
Big Larry offers some great advice. From all his points, I'd only challenge two.

1. I manage to geocache without a magnetic compass without much problem. I'll admit it would be nice-to-have, though. you could buy a separate compass, though.

2. I'm perfectly happy without a barometric altimeter and find that the GPS altitude reading is usually very close to accurate (+/- 5 meters). It also doesn't need calibrating, which the barometric one always will.
I agree these features are somewhat expensive, perhaps doubling the price as seen in my previous post, and could be of marginal use depending on application and relative precision of other measurements. So you need to make sure you need them. Let me explain what I see in detail.

1. Compass for Geocaching
When geocaching, as you move in, you want to know the direction to go to the cache and how far. This can be done in two ways.

A. You look at the map screen and see you and the geocache waypoint and move toward it.
B. The compass screen tells you which way to turn and how far to go.

I found the compass screen is so much better that the map is effectively useless. It takes a while for your mind and kids to try and interpret from the map which way is which each of the hundreds of times you look at it. Also, to avoid running into a tree, most of the time you're stopped with someone peering over your shoulder while looking at the screen. The GPS compass only works if you keep moving and are looking at it while moving.

When doing MTB, I find I don't need the magnetic compass as I usually just display the big number odometer with one of the indicators programed to show a count down to the next waypoint. So I know I'm going the right way when that display gets smaller. But I'm usually riding on a defined trail and don't need to know the precise direction, unlike geocaching where the direction to an off-trail location is very important.

So when doing MTB, I turn off the compass to save battery. However, there has been a few times for MTB in the woods when I needed it, turned it on and did a couple spins to calibrate.

Barometric versus GPS Altimeter
A GPS position for a given time difference of the satellites and reception time error will be more accurate the greater the angle between the satellites, with direct opposite being the best for determining position accuracy. Because the vertical altitude gets it's signal from both sides of the planet from all the satellites, the position isn't as accurate. I find its typically about 3X less accurate than position. So for 15' off horizontal, it would be 50' off vertical. But as mentioned below, I have seen bigger.

The Garmin accuracy specification for horizontal position is around +/- 15 meters or 45' for 95% confidence. The average error is maybe half that. I find the satellite display on my eTrex usually indicates 15' to 28' horizontal position accuracy, and the accuracy based on repeating known points with good reception is indeed about 10' to 30' error. But again, the vertical error is likely much worse, and like the horizontal error will go both ways from time to time.

I so happen to wonder about this question two weeks ago, and also wondered if I could roughly calibrate the altimeter with the GPS altimeter. So checked the GPS altitude a few times on a ride last week that started at 850' elevation. Within 10 minutes on some checks while suiting up, I got readings anywhere from 750 to 930, or +80 /-100' - all while sitting in the same spot. I gave up on trying to use it. So my eTrex doesn't get the altitude accuracy you claim. I have heard the newer SiRF chips can get much better vertical accuracy with the greater number of satellites received. I'd like to see real number on that. What unit do you use SwissBuster?

The issue with a barometric altimeter is drift. To give a feeling of how much drift you can get, I just reviewed my GPS logs and recorded the altitude difference at the beginning and end of a ride for many rides. I did this for a typical 2.5 hour ride and for 5-8 hour rides. I sometimes rounded a couple feet to 5' on larger errors. This is the worst case drift from beginning to end of the ride. At the middle of the ride, the drift would be about half, for instance. Here's the results for my eTrex barometric altimeter.

Total altitude drift for 2.5 hour ride (in feet):
-20, 20, 8, 35, 30, 75, 38, 35, 13, -28, 15, -20

Total altitude drift for 5 to 8 hour ride (in feet):
60, 8, 10, 60, 15, 85, 45, 30, 80, -60, -10, 40

Again, at mid-ride the error will be about half that above. I remember going up some peaks with well marked altitude at mid-ride, I get upset if I'm more than 10 feet off, and it doesn't happen often. By comparison, my eTrex GPS satellite altitude will bounce by approximately +/- 100' or 200' difference at the same spot within a few minutes. I'd say I may be getting 5X to 10x greater accuracy with the calibrated barometric altimeter.
 

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Foretrex 201

BigLarry said:
What unit do you use SwissBuster?
A foretrex 201, which I think has the same chip as the eTrex.

Thanks for the science bits. I guess I could be getting better readings based on my geographic position and strong signals (limited tree cover). My testing has been far less scientific - I usually check the readout whenever I am near a spot with a marked altitude. It 'roams' somewhat but usually only by +/- 1m.

I continue to be amazed by the accuracy, both horizontally and vertically, of these toys.
 
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