[stairman]

I have just recently been using one for the vehicle to find addresses to hook up satellite tv. What a lifesaver and now reasonably priced. Ive had an e-trex for years but it has no maps or roads in it and is only good to find a waypoint youve already punched in. Excellent for hunting for sure. I think one with maps/roads etc would be a welcome addition in a mobile get home bag. I do have a backup compass and maps of the areas I travel but unless your following a road its not gonna be so easy to find your way back, and they work on battery power for a while. However if the GPS sat goes out in the caos its useless.

[vthompson]

I have always wanted to see/use a handheld GPS unit, but I am not going to pay good money for something that I have never tried before. I don't know the first thing about them and I don't know of anyone that has one for me to check out. If someone can explain them to me, I am all ears.

[Ron Fontaine]

Yes, GPS can stop working at any time - either your GPS unit or even the entire system. So be sure to carry a map and compass and know how to use them.

[Unswydd]

I don't particularly trust them. I just bought an Orienteering Compass and am trying to learn how to use it with my topo map of The Winds in WY so I'll be comfortable with it when I go in Aug. Very intersting piece of gear.

[Celticwarrior]

It is a good way to check yourself as you learn to orienteer with map and compass though. Nice to have a relatively foolproof method to tell you whether you did good or you still have some studying to do. LOL

[Unswydd]

I think I'll be okay with the compass. I used to hunt a lot out in the desert with topo maps all the time, but alas that was 30 years ago. LOL Good grief I'm gettin' old! I think I can do it. Gotta be like the little engine who could!

[Dick]

Heyzeus wept.
I wrote an eloquent and poignant essay on GPS handhelds yesterday and it's not here now. Damn whatevers!!

I give it another crack if I find time today. You can all oooh and aaah now in anticipation if you wish.

[Dick]

GPS is a useful tool to have to complete your navigation tools. It should not be used as an alternative to map and compass, but as a compliment.

The units are not particularly good for navigation (used like a compass) because if / when you lose your satellite signal you have lost your compass. Also, if you are stationary the GPS will not work as a compass. You need to be moving for it to work as a compass. The worst thing is that it will still give you an azimuth when it’s not working, just the wrong one!

Most useful features include the ability to record a “waypoint” or “landmark”. You can landmark a good fishing spot on a lake, your food cache, your vehicle, etc… Essentially you are getting a map grid for those locations.

Some units allow digital maps or orthophotos to be loaded into them, allowing real time positioning. Most will record “tracks”, so you can see exactly where you traveled, how far, average velocity, etc… These tracks (and “landmarks”) can be loaded back up onto a map if so desired.

You can use it to give you an azimuth between two landmarks, as well as a distance, and estimated travel time.

Positioning with GPS is accomplished by satellites triangulating on your position. The satellite signal has an assumed velocity. The satellites all know where they are relative to one another, so the time it takes for the satellite signal to reach your receiver represents a distance. You therefore need a minimum of 3 satellites for a position, although 4 will give you a more accurate position including elevation.

The assumed velocity of the sat signal is just that, assumed. Differences in atmospheric moisture and density can affect the time it takes and the strength of the signal reaching your receiver. Most, if not all, receiver will indicate the “accuracy” of the position based on the strength of the signal. On a good day it may say “Accurate to within 4 meters”, whereas on a bad day it may say “Accurate to within 36 meters”.

Accuracy is impacted by satellite orientation also. If the satellites you are using are all stacked together in the southern sky you will not get a good fix, whereas if they are all around you (N,S,E,W) you will get a much better position.

Most of the satellites are pseudo equatorial. The further north you travel, the more southern the satellites. This can be problematic if you have a ridge or mountain blocking the southern sky.

The receiver will automatically pick the best satellites based on signal strength and spatial orientation, and will switch satellites at any time to optimize the units performance.

The signal will not pass through water. Putting your hand over the receiver is enough to block the signal. Heavy forest cover (trees have water) will interfere and possibly block a signal. The worst I encountered was when the trees were heavily laden with wet snow.
The satellites are constantly moving in their orbits, so if you lose a signal chances are you will get it back if you wait. Alternately, just move from your present location. Sometimes a few meters is all that is necessary.

The beauty of the GPS is that you can navigate without having to pace and follow a precise azimuth. If you record a landmark and mark it on your map, you can wander around willy nilly en route to your destination. It is important to take additional positions along the way and mark them on your map, just in case you lose signal or your unit malfunctions. You can always go back to the last ‘known’ point and compass back to your home base. Your unit doesn’t need satellites to calculate distances and azimuths from pre-recorded landmarks.

You can get your map position either by location via grid reference, or you can landmark a known location (i.e. road intersection) and then ask the unit the azimuth and distance to that landmark. Then just use your compass (protractor and ruler) to mark your new location. Landmark again, and repeat.

Despite the potential “weak links” GPS is very reliable, just not entirely reliable.

Hope that all makes sense.

[heysmithy]

I got the Garmin 205(?) model at walmart recently on clearance for $110. It has already saved some gas money on road trips by guiding me straight to my destination, instead of me driving around looking for it like I have done in the past. I'm hoping after a couple of years of use it will pay for itself completely just with saved gas money.

Ive got to say, I couldn't be happier with the purchase. It has phone numbers for every business so I don't have to mess with directory assistance anymore. I typed in "gun" on my GPS and I found a local gun store that I didn't even know existed! And the other day my wife wanted to go out on a date but it was raining and we didnt know what to do, I clicked the "entertainment" button and got an instant list of our options. For convenience in every-day urban use, its definitely well worth the money.

As for outdoors/hiking use, my brother has used his Garmin GPS more for this purpose than I have. A GPS just really isn't my style for out in the woods hiking and whatnot. I much prefer a plain ol' compass. It just seems that by going primitive you get a better feel for your surroundings, and a better connection to nature, as retarded as that may sound. I feel like a native animal of the woods when I'm out there, but I wouldn't feel that way if I was walking about with glowing electronic devices. However if I was lost and panicky and desperately trying to make my way back to camp, I suppose a GPS would be my best friend.

[Dick]

Originally Posted by heysmithy

...It just seems that by going primitive you get a better feel for your surroundings, and a better connection to nature, as retarded as that may sound. I feel like a native animal of the woods when I'm out there, but I wouldn't feel that way if I was walking about with glowing electronic devices...

I find quite the opposite. With compassing my focus is on keeping a straight line and knowing my approximate distance travelled. I find that I don’t get much opportunity to “smell the roses”. If I want to step off my line I have to remember / record my distance and mark the spot so I can return and continue compassing. In contrast, with GPS I can wander about freely. I can check out the valley, the ridge, and scoot over to the pond and get a good feel for the layout of the land and the available 'survival' resources... knowing that I can relocate myself on the map at pretty much any time I want.
Also, with map and compass obstacles can be a pain. If you meet a fast flowing creek and have to move up or down stream to cross it, it may be difficult to get back on your line. Circumnavigating cliffs, bears, and any number of other obstacles require careful and somewhat laborious consideration with a map and compass.