GPS: Do I want one with mapping?

[adkayaker]

My mountian hikes, when solo, are always on marked trails so other than downed leaves in autumn, am usually not concerned about losing the trail. However, in the Adirondack and Vermont lowlands, I plan on increased bushwacks off trails and roads in pursuit of nature photography subjects. I always carry map and compass and the skills to use them. But in considering my first GPS, would a basic non-mapping model with backtracking be sufficient or is it smarter to obtain one that I can use purchased topo maps with?

 

[Dunbar]

I would definitely get one with mapping capability. Very useful in a variety of situations.

 

[DougPaul]

I highly recommend a mapping unit. With the mapping, you can see where you are at a glance and generally transfer your location to a paper map by inspection. Without the mapping, you have to use lat and lon to transfer your location to/from a map--a slow and error-prone process which may be difficult to do in bad conditions. Many mapping hiking GPSes can also be used while driving while a non-mapping GPS would be pretty useless.

Non-mapping GPSes can plot your track, but it is on a blank background and of limited use. (Mapping GPSes will plot the track on the map.) One way to improve the useability of a non-mapping unit is to put waypoints at nearby summits, trail junctions, trailheads, and points of interest to make the track plots more meaningful. While this helps, plotting the track on a map is still much more useful.

The most popular hiking GPS seems to be the Garmin GPSMAP 60CSx, recently discontinued (but you may still be able to buy new or used units). The successor is the GPSMAP 62s.

Garmin sells a 100K scale US topo and regional 24K topos as well as road maps. There are also free road and topo maps (of varying quality) available at http://www.gpsfiledepot.com/[/url]. You can get a free copy of Garmin Mapsource (runs on your computer) to manage the maps, routes, tracks, and waypoints--see http://www.gpsfiledepot.com/. (Garmin's maps come with Mapsource if you buy them on DVD or CDROM.)

Garmin (and I presume other manufacturers') GPSes can hold several types (eg road, topo 100K, topo24K) of map simultaneously and you can choose which one to display.

One other (often important) use for the GPS is finding the trailheads...

Doug

 

[MichaelJ]

Get the mapping. If you ever need it as an emergency safety device, you will appreciate having a topo map loaded instead of having to transfer the given coordinates onto your paper map to figure out where you are (assuming your paper topo map has a UTM grid on it). Also, not only is it helpful as Doug says for finding trailheads (miles and miles of unnamed logging roads!) you can get routable street maps and use it for driving navigation.

Better to have and not need, IMO.

 

[Little Rickie]

How much money do want to spend?

How far off trail or a road would you be?

Will knowing where you and back tracking be all you will need or do you want the big picture?

 

[TomD]

I am a novice GPS user. I thought they all had maps. Shows how litle I know. I have a Garmin GPSMap76CSx (similar to a 60CSx from what I have read) that I got off Craigslist. The original owner had used his for hunting and had everything that came with it new, plus a card with a map on it. I bought an extra card and as DougPaul suggests, downloaded MapSource and free topo maps from www.gpsfiledepot.com. It took a while to figure out how to get the map sectors I wanted, but it wasn't ridiculously hard. I got help from members of the forum on the gpsfiledepot website, which was very useful. The site has tutorials including how to get MapSource, so if you need to figure something out, that's the site for everything Garmin.

I just took a quick look at eBay and there are hundreds of units for sale there, plus I imagine there are many on Craigslist as well, so if money is an issue, I'd look at getting a used one.

Also, I called Garmin customer service for help when I was downloading maps onto a car unit for a friend and it wouldn't work right. The guy I got was here in the US and very helpful, so that is another plus for Garmin.

 

[adkayaker]

Etrex 20-30 series

I was looking at the newest released models with mapping, the 20 and 30. Those screens are really small!

 

[DSettahr]

Without the mapping, you have to use lat and lon to transfer your location to/from a map--a slow and error-prone process which may be difficult to do in bad conditions.

UTM is much better than Lat/Long to look at your GPS coordinates, and plot your general location on a topo/hiking map quickly and easily, because the scale is the same in both the X and Y axis. With a little bit of practice, you can also get quite good at it without having to resort to any complicated math, since it's a 10-based system which is much easier for most people to use than the 60-based system used for degrees/minutes/seconds.

Regardless, at this point GPS units have progressed enough technologically and become cheap enough that there really is no excuse for not getting one with the mapping capability. Just be aware that the maps usually cost extra, and don't come pre-loaded with the GPS.

 

[DSettahr]

I was looking at the newest released models with mapping, the 20 and 30. Those screens are really small!

They are small, but the resolution on them is decent. I've never had any problems with them.

I wouldn't expect to be able to use a GPS by itself for complicated backcountry navigation anyways- your'e still going to want your hiking/topo map out and ready, which makes it much easier to see the "big picture" of the surrounding terrain. The map on the GPS screen is more for showing precisely your current location than it is for showing terrain over a large area.

Having a compass out and ready can't hurt either- many GPS units (like many of the etrexes) don't actually have a built in compass. The navigation function only works accurately as long as you keep moving, since it uses successive GPS coordinates to figure out what direction you're traveling in and then point you in the correct direction. As soon as you stop moving, the compass on the screen reverts to indicating that north is straight ahead, regardless of what direction you are facing. It can be a little bit confusing until you get used to it.

 

[Nessmuk]

I wouldn't expect to be able to use a GPS by itself for complicated backcountry navigation anyways- your'e still going to want your hiking/topo map out and ready, which makes it much easier to see the "big picture" of the surrounding terrain. The map on the GPS screen is more for showing precisely your current location than it is for showing terrain over a large area.

Having a compass out and ready can't hurt either- ...

Exactly. Thanks for pointing this out D, (before I felt compelled to do the same, and that M&C skills alone should be up to where ever one travels, without OR with GPS aid).

 

[DougPaul]

UTM is much better than Lat/Long to look at your GPS coordinates, and plot your general location on a topo/hiking map quickly and easily, because the scale is the same in both the X and Y axis. With a little bit of practice, you can also get quite good at it without having to resort to any complicated math, since it's a 10-based system which is much easier for most people to use than the 60-based system used for degrees/minutes/seconds.

That depends on what you are used to using and what you are using it for. I started ~30 years ago with ocean nautical navigation where/when lat-lon was the standard. For me it is simpler to stay with what I know.

UTM is at its best for local area work, but does not work as well for long distance travel which crosses zones (eg aeronautical and blue-water nautical). Lat-lon works equally well everywhere.

I recently needed to do something with UTM and found it to be annoying. To each his own.

The GPSes allow one to set the coordinate system so one can use whichever one prefers.

Doug

 

[bikehikeskifish]

The Garmin CS and CSx (60/76) have compass/altimeter instruments built in which work when stationary.

Tim

 

[DougPaul]

I was looking at the newest released models with mapping, the 20 and 30. Those screens are really small!

It's a tradeoff: larger screens are less portable.

I use a paper map for the big picture and the GPS for the small picture and/or my location and direction of travel.

The 60/72 series (older) and the 62/78 series (current) are Garmin's top of the line--the eTrex line has been a somewhat reduced feature line since 60/72 series came out.

Doug

 

[DSettahr]

That depends on what you are used to using and what you are using it for. I started ~30 years ago with ocean nautical navigation where/when lat-lon was the standard. For me it is simpler to stay with what I know.

UTM is at its best for local area work, but does not work as well for long distance travel which crosses zones (eg aeronautical and blue-water nautical). Lat-lon works equally well everywhere.

I recently needed to do something with UTM and found it to be annoying. To each his own.

The GPSes allow one to set the coordinate system so one can use whichever one prefers.

Doug

It does indeed depend on the usage, and I agree that for long distances that are almost global in scale, lat-long or another geodetic system that works on a sphere would be better.

The thread is on a hiking message board and is about climbing mountains, though, not about sailing or flying- hence my (I think) reasonable assumption that the discussion was about GPS navigation as it pertains to backcountry travel on a small scale in terms of miles or tens of miles at most. I apologize for the confusion!

 

[DougPaul]

Re compasses:
Garmin's "sensor" feature set includes both a barometric altimeter and a magnetic compass. It is generally found on their higher-end hiking GPSes. (All GPSes have a GPS "compass".)

The two compasses are measuring different things:

The magnetic compass, of course, indicates direction with reference to the local magnetic field whether the GPS is moving or not. If you turn the GPS body, the needle should stay stationary. There are 2D compasses which need to be held level and 3D compasses which need not be held level. The compass must be calibrated every time you change the batteries so it can compensate for the magnetic fields from them.

The GPS compass indicates the direction of movement no matter what the orientation of the GPS body. Thus when one turns the GPS body the direction indicator will stay fixed with respect to the GPS body. The indicator will change only if you change the direction of movement or stop. The GPS compass need not be calibrated.

The 60CSx has a settable threshold so it can automatically be switched to the magnetic compass when moving slower than the threshold switched to the GPS compass when moving faster than the threshold. Both compasses can also be set to read out magnetic or true bearings. (The GPS knows where you are and can do the conversion internally.)

FWIW, I rarely use the magnetic compass (I set the speed threshold to 0)--my mechanical compass is more accurate, sights better, doesn't need to be calibrated, and doesn't require batteries.

Doug

 

[DougPaul]

The thread is on a hiking message board and is about climbing mountains, though, not about sailing or flying- hence my (I think) reasonable assumption that the discussion was about GPS navigation as it pertains to backcountry travel on a small scale in terms of miles or tens of miles at most. I apologize for the confusion!

My point for hiking is that it is a personal preference.

If one is working with a group (eg SAR), one should use whatever the group is using to minimize the confusion and conversion errors. But beyond that, personal preference should reign.

Doug

 

[adkayaker]

Example of use-bushwhack exploration on public lands off Lake Desolation road looking for breeding birds in spring. Limited topographic features.


So new etrex 20-30 or older but better featured 60-62 suggested?

 

[DougPaul]

Re altimeters:
The altimeters (GPS and barometric) are unaffected by motion and the GPS body orientation.

The advantage of the barometric altimeter in the "senor" units is that by using the GPS altitude to continuously auto-calibrate the barometric altimeter the system is usually more accurate than either alone. Auto-calibration can take an hour or more (the error decreases continuously until it gets within spec) so it works best when the GPS is left on continuously. When I reach a peak, my altimeter is usually within 10 feet of the surveyed altitude.

Doug

 

[DougPaul]

Example of use-bushwhack exploration on public lands off Lake Desolation road looking for breeding birds in spring. Limited topographic features.

GPSes are very good for navigating around featureless boggy areas--when one stand of trees or reeds or each floating island begins to look like another it can still tell you where you are... It can also be very handy for finding the inlet or outlet of a sluggish boggy lake. (I have never been to Lake Desolation road so I don't know what it is like--in general GPSes can be very useful in featureless terrain.)

So new etrex 20-30 or older but better featured 60-62 suggested?

I expect that either will do the job and you will probably be happy with either. (I know, I'm not much help... )

One issue for you might be the mounting--if you are walking the 60/62 series is best when oriented vertically (ie in a pack pocket). If you are in a boat, the 72/78/eTrex series might be better because they are designed to sit on a flat table top or boat deck. (These GPSes still work pretty well if not oriented optimally.) The 72/78 series also floats (at least with alkaline batteries--I don't know about with heavier NiMH). In any case, I suggest that you add sufficient floatation if you carry it loose on a boat. The 60/62 series also has a nice foam-neoprene case for it, I'm not sure about the others.

Doug

 

[Remix]

Yes, get a mapping unit. In addition to all the reasons cited above, they generally come with more powerful CPUs and memory-- handy for storing every hike you have ever made, waypoint storage with detailed notes, point and shoot, and other features having nothing to do with maps.