Using Map/compass And A Gps

[RaisedByWolves]

Recently, while out in the mountains of western North Carolina (my home) I was caught with the most dreaded of GPSr messages..."weak signal. Move to a clear view of the sky". Um.... I'm 2600 feet high in a clearing with a good view. How will I ever find my way to that elusive cache?! Well.... seeing as I had been playing in the remote appalachians for most of my life, I know the value of a good topo map and a compass AND how to use them. Needless to say, I found where I was and where I wanted to go without the need of AA batteries, clear sky and an electronic gizmo.

Now, I'm in no way coming down on the use of a GPSr for this great game. Nor do I dislike those that rely on them while hunting, fishing, backpacking or geocaching. GPSr's are a great tool and SO much fun to play with, but I think you all can agree with me that their use can only be relied upon in limited scopes. I have some questions for you all, however....

 

First.... why oh why do you all give coordinates to caches in dd.mm.ss.ss? If you've ever used a USGS topo map (7.5 minute series) you know that trying to get accurate lon/lat coord's with them is nearly an excersize in futility. Especially if you don't have a Quadtool. The lon/lat tics aren't printed very readily and unless you have a yard stick, good luck getting aligned (especially in the dark). Personally, I an set up to use the UTMsetup on my Garmin with NAD27 coord's in order to get accurate coroboration with my maps. Using NAD27 and UTM, I can get within 10 meters on a topo (better than my Garmin in most locations).

 

Second.... how many of you acually understand the UTM system?

 

Again, I'm in no way trying to make anyone feel "inferior" or ignorant here. I'm so excited to be part of this group and from what I've read in these forums, you all seem to be pretty down-to-earth folks (no pun intended, hehe) of high moral fortitude. I'm simply asking a question of mechanics pertaining to the Great Game.

 

I hope to hear some good input on this.

[+IV_Warrior]

 

First.... why oh why do you all give coordinates to caches in dd.mm.ss.ss?

We don't. We use HDDD MM.mmm because that's how the site is set up to enter cache coordinates. If the site was set up for degree minute second, everyone would use that.

Second.... how many of you acually understand the UTM system?

I don't know, but I'd bet its a small percentage of the cachers who fully understand ANY of the coordinate formats, and a similar percentage who actually CARE to understand more than how to enter the coords into their GPS and hit "goto".

[+Metaphor]

I had a similar discussion with a friend yesterday out on a boat. His son, who is studying in the Adirondacks, just bought a gps. Dad thought is was great until I asked if the son knew how to use a topo and a compass. He didn't, and I explained the inadequacy of gps receivers -- all the usual problems. Later this summer, the three of us are going out and I'm teaching a little basic map 'n compass..

 

Reliance on electronics is a common problem with ocean sailing (and power boating). A lot of those who get lost and need assistance don't know how to use the basic compass for direction, and when electronics fail, with no sight of land, they get lost pretty quickly. It's not necessary to be able to use a sextant, but at least be able to use a compass.

 

I'd almost say it should be a prerequisite for gpsr use-- my compass has never failed me...

[+alexrudd]

 

First.... why oh why do you all give coordinates to caches in dd.mm.ss.ss?

We don't. We use HDDD MM.mmm because that's how the site is set up to enter cache coordinates. If the site was set up for degree minute second, everyone would use that.

I think HDDD MM.MMM is the format most GPS receivers are set to out of the box. Rather than explain to countless newbies how to change formats, geocaching.com just adopted it for simplicity.

 

Personally, I have never run across UTM so I'm not exactly sure what it is. Using the other formats is easy understand, and I'm sure UTM would be too, but I never have a need to use UTM.

[+thedeadpirate]

First.... why oh why do you all give coordinates to caches in dd.mm.ss.ss?

 

I think I'd agree that TPTB went with the DD MM.MMM format because it's the default for most gpsr's.

 

Second.... how many of you acually understand the UTM system?

 

I don't understand it at all. I know it exists, I've seen it on cache pages, but I have not attempted to learn it.

 

That being said, I think it is wise for anyone venturing out into the woods have at least rudimentary skills at using a compass. I don't ever venture out more than a mile or so, but I always carry a compass with me. I don't think I could find a cache by compass alone, but I could find my way back out if my gpsr died.

 

I also agree that anyone who is into long hikes, sailing, any type of activity that will take them far off the beaten path should be trained in using a map and compass. Electronics fail for a multitude of reasons.

 

I think I will go check into UTM now...

[RaisedByWolves]

Woops, my fault... I meant to say HDDD MM.mmm . Thanks for the clarification IV Warrior.

 

As for the technicallity of UTM, athe most basic, its very simple.... the grid lines on your local topo map (1:25,000 or 7.5 minute scale) are UTM not longitude / latitude. That little misunderstanding had me stumped years ago when I first thought that with a map and compass alone I could find my way "there and back again". Silly child, you need to learn how to use them, they dont have a mind of their own ::snicker::

 

I guess it's true what they say; with age comes wisdom (getting lost at age 8 will do it to you also).

 

Anyhow, after a moment of clarity (they're few and far between), I realized two things:

1.) We use the format we use with GPSr's in mind, not map/compass. Why know deg.min.sec when the GPSr points you in the right direction?

2.) With the simple push of a button, I can convert ANY coordinate system to whatever coordinate system *I* prefer.

I know what happened... I stopped to think and forgot to start again.

[+fizzymagic]

First.... why oh why do you all give coordinates to caches in dd.mm.ss.ss? If you've ever used a USGS topo map (7.5 minute series) you know that trying to get accurate lon/lat coord's with them is nearly an excersize in futility.

That's not the fault of the coordinate system.

 

Second.... how many of you acually understand the UTM system?

Me! I do! In fact, I suspect I understand it better than you do. Enough to understand why it is not an appropriate coordinate system for everything.

 

You see, there's this little problem with it: the Earth is not flat. Now, I know that the maps you use are flat, and that understanding coordinates on a flat surface is easier than understanding spherical coordinates.

 

Unfortunately, reality doesn't conform itself to what you find easiest. In particular, UTM is quite bad for waypoint projection and for directional triangulation over distances greater than about a mile.

 

By the way, just for the sake of completeness: you do know that USGS topo maps are not UTM projections, right?

Edited July 3, 2006 by fizzymagic

[+Yellow ants]

In particular, UTM is quite bad for waypoint projection and for directional triangulation over distances greater than about a mile.

 

It is, however, quite good for solving geometrical cache puzzles, since UTM coordinates are a cartesian coordinate system (as long as you don't stumble across zones, of course).

[+Mule Ears]

It doesn't really matter what coord system the site uses by default; it's completely painless to convert to your preferred system. Once the target is accurately transferred to a map, who cares what the coords are? That's not really the way we navigate outdoors anyway. We recognize landmarks and relate them to features on the map.

 

Getting, having and maintaining decent map-and-compass skills are very important for wilderness navigators. They let us work around equipment failures, increase our confidence and survival ability, and allow us to feel superior to clueless trail hikers and arrow followers. That last one's really the best.

[+fizzymagic]

In particular, UTM is quite bad for waypoint projection and for directional triangulation over distances greater than about a mile.

It is, however, quite good for solving geometrical cache puzzles, since UTM coordinates are a cartesian coordinate system (as long as you don't stumble across zones, of course).

Slight correction: it is good for solving geometrical cache puzzles that only use distances, not angles. There's a great example of this problem in a very famous puzzle cache that will remain nameless. It uses UTM for projection over a distance of around 25 miles. The (incorrect) answer you are supposed to get is off from the correct answer by almost 2 miles!

[+Poidawg]

While caching I always take my GPSr - it has all the information on where the goodies are hidden, my compass and a map of the area (Topozone print out). While Orienteering, I also take all three. I use long/lat because it was what I was taught to use first, it is what my GSPr is set for. I am learning to use UTM - slowly, but am willing.

I do know people have been using long/lat for a long time without issue. Just because UTM comes along does not mean it is better or easier for everyone. I for one am glad to have the choice to choose.

[+Yellow ants]

Slight correction: it is good for solving geometrical cache puzzles that only use distances, not angles.

 

Of course. Good, fast, cheap; you can have two. No wait, that's software! Distance, azimuth, area, you can have one ... sort of.

[+Team Cotati]

We rely upon our GPSr and our wits exclusively. We do not own a compass. We really really have gotten a significant amount of enjoyment out of this here geocaching thingie. I know that someday, we are going to get lost and be eaten by a bear or a zebra or something equally dangerous. This possibility adds excitment to our adventures.

Edited July 4, 2006 by Team Cotati

[+CheshireFrog]

We rely upon our GPSr and our wits exclusively. We do not own a compass. We really really have gotten a significant amount of enjoyment out of this here geocaching thingie. I know that someday, we are going to get lost and be eaten by a bear or a zebra or something equally dangerous. This possibility adds excitment to our adventures.

 

It's only possible to get lost on the way to the cache. Once you find the cache you will see the path you were supposed to take in the first place.

 

Oh, and it's possible to get lost by following me anywhere.

[+Lighteye]

Here's one for you:

 

My60CSX' electronic compass got a little jiggy one day 9 miles out into a preserve, and I was at a T in the trail. No matter that I was having to recalibrate it it every 10 minutes, it was consistently either 90 or 180 degrees wrong. Completely unpredictable.

 

I was already suffering from heat exhaustion, and my 8 liters of water were gone. Thanks to my lensatic compass and map printout, I was able to walk out of there, and save the cost of a medevac, and around here, it is $25K+ This is no joke, and no fairytale. Good Uncle Sam trained me all those years ago, and it saved my life, probably. I made it out to the hardtop and called the spouse, who was able to pick me up.

 

Anyone who attempts wilderness caches without at least a minimum of map/compass and landnav abilities is asking for the worst to happen.

 

I am holding off on going after the rest of the caches in this area until the winter, BTW. 16+ miles in the Florida sun through level 4 terrain will cook you drier than bad beef jerky. Just the thought of a second mortgage to pay a medevac chopper and the resulting embarrassment is enough to convince me to stay sharp on my map reading skills.

[+thedeadpirate]

It's only possible to get lost on the way to the cache. Once you find the cache you will see the path you were supposed to take in the first place.

 

This is so true so many times. There's nothing like bushwacking your way to a cache and then finding a trail next to it. What the gpsr shows as the shortest distance is not always the best way in.

[+TheAlabamaRambler]

I keep a compass with me, but rarely a map, since I don't do much wilderness hiking and knowing which way to the truck or to the nearest road is sufficient.

 

I have only used it once, on a cache where you had to compute and follow reverse azimuth. I might have needed it once, when I fell on a steep mountain trail and smashed my GPS, but since I was only a mile from the truck and knew the trails it wasn't an issue.

 

I think you may find a correlation between folks who rely on technology and folks who are underinsured... I have backup systems for all technology because I know it may fail at any time, just as I have quite good insurance for risks I hope never occur.

 

A compass is cheap insurance!

[+Searching_ut]

...... If you've ever used a USGS topo map (7.5 minute series) you know that trying to get accurate lon/lat coord's with them is nearly an excersize in futility. Especially if you don't have a Quadtool. The lon/lat tics aren't printed very readily and unless you have a yard stick, good luck getting aligned (especially in the dark). Personally, I an set up to use the UTMsetup on my Garmin with NAD27 coord's in order to get accurate coroboration with my maps. Using NAD27 and UTM, I can get within 10 meters on a topo (better than my Garmin in most locations).

 

Actually, last I checked, I had over 300 quads, many of them so old and worn I really don't dare unfold them anymore. A major problem with Quads is the number of them you need to cover a fairly small hiking trip, and the cost. GPS units with their storage capacity, navigation ability, and accuracy mean I rarely use small scale maps like quads anymore. I virtually alwasys carry a 1:100,000 or even 1:250,000 scale map and compass with me though.

 

As for navigating to within 10 meters of a location using a Quad, that's going to be something that happens on few and far between occasions. Last time I checked, the USGS was only hoping for accuracy of something like 12 meters when they made the maps, and when you factor in the lack of precise triangulation spots, compass errors, and measuring errors getting under 12 meters (around 1/50th of an inch on a quad) is going to be tough. I've never had consistant accuracy to anywhere near that degree in real life.

 

As for the coordinate system used by geocachers, think of it like the metric system. Makes things a much more universal thing which if you've traveled and used available maps much you'll be aware that UTM isn't. The nice thing about GPS is that you can get data out of it that allows you to work with just about any type of map out there.

[+edscott]

.......

As for navigating to within 10 meters of a location using a Quad, that's going to be something that happens on few and far between occasions. Last time I checked, the USGS was only hoping for accuracy of something like 12 meters when they made the maps, and when you factor in the lack of precise triangulation spots, compass errors, and measuring errors getting under 12 meters (around 1/50th of an inch on a quad) is going to be tough. I've never had consistant accuracy to anywhere near that degree in real life.

 

As for the coordinate system used by geocachers, think of it like the metric system. Makes things a much more universal thing which if you've traveled and used available maps much you'll be aware that UTM isn't. The nice thing about GPS is that you can get data out of it that allows you to work with just about any type of map out there.

 

Using the typical USGS quad at 1:50,000 or 1:25000 may not get some people close enough, but that coupled with a good aerial photo seems to be fine for me. I personally would think of the UTM as being more like metric than degrees and minutes.. but I just use maps and meters.

 

We rely upon our GPSr and our wits exclusively. We do not own a compass. We really really have gotten a significant amount of enjoyment out of this here geocaching thingie. I know that someday, we are going to get lost and be eaten by a bear or a zebra or something equally dangerous. This possibility adds excitment to our adventures.

 

Me too... only the opposite We rely upon our map and our wits exclusively. We do not own a GPS. We really really have gotten a significant amount of enjoyment out of this here geocaching thingie. I know that someday, we are going to get lost and be eaten by a bear or a zebra or something equally dangerous. This possibility adds excitment to our adventures.

[hikin4fishin]

Slight correction: it is good for solving geometrical cache puzzles that only use distances, not angles.

 

Of course. Good, fast, cheap; you can have two. No wait, that's software! Distance, azimuth, area, you can have one ... sort of.

 

Distance, azimuth, area... it's all just math. No wait, don't run away.

 

As long as you know the declination between Magnetic and True North, and you have a map with reasonably accurate positions for two objects that you can shoot an azimuth to from your position, all the rest is just calculation and/ or plotting.

 

A cheap compass can steer you wrong or it can help you find your way, but a really spensive one can get you lost even more precisely, if you don't know how to use it properly.

 

I don't know how. I'm learning. It's really cool though. I made the mistake of buying a cheap eBay 'lensatic compass' . There's a lot out there and they're cheap. They're also near useless.

1. The sight wires are not aligned with the center axis
   
2. The index lines on the face are not aligned with the center axis
   
3. The needle 'settle time' is horribly slow
   
4. The needle is apparently not balanced for my region, as it was cheaply made in a country in a different region
   
5. The compass cannot be opened and laid flat on a map as the sight wire screws are sticking out too far (cheaply made)
   

[+fizzymagic]

As long as you know the declination between Magnetic and True North, and you have a map with reasonably accurate positions for two objects that you can shoot an azimuth to from your position, all the rest is just calculation and/ or plotting.

 

Actually, no. Using UTM and maps, there is also Grid North. Which changes with position. A straight line on a UTM-calibrated map is not a straight line on the surface of the Earth.

 

And so on...

 

It's great to see that you are interested in learning about this stuff. Since I started geocaching, I have learned a lot about geodesy. And I've discovered that it is a lot more complicated than I ever thought!

[edmcnierney]

Actually, no. Using UTM and maps, there is also Grid North. Which changes with position. A straight line on a UTM-calibrated map is not a straight line on the surface of the Earth.

 

But there aren't any straight lines on the surface of the Earth - it's round! And that's the fundamental issue here - you're comparing a geographic coordinate system (latitude/longitude) with a projected coordinate system (UTM), and one operates in ellipsoidal space (the surface of the Earth) and the other operates in planar space (the flat surface of a printed map).

 

I just wanted to point out that your comments about UTM coordinates really apply (in general) to projected coordinate systems, and aren't specific to the UTM projection. UTM has lots of benefits (how far is it from 42.5860N, 71.5550W to 42.9558N, 71.0799W?) but any map projection, being flat, has to make some compromises. You get to pick certain properties that DO work correctly, but others fall apart. The classic example is the Mercator projection, which badly distorts areas and shapes, but on which lines of constant compass declination are straight lines. Great if you're a 16th-century marine navigator, but lousy in the woods.

 

UTM is an excellent projection for (most) geocaching work because it's easy to understand and use over short distances, and provides little distortion over short distances. And while the printed USGS topographic maps don't use UTM (but DO use other projections, with similar limitations), when the USGS decided to create digital topographic maps (DRGs) they made ALL of them in the UTM projection.

 

Ed

(TopoZone Map Guy)

[+CharlieP]

I always carry a compass, and if I am geocaching in a remote area where I may need to go off-trail, or where the trails are not well marked, I will also carry a topo map. I long ago learned from boating that it is not enough to know your position and your destination, you need to know what is in between. I often use UTM because many topo maps have UTM grids.

Edited July 7, 2006 by CharlieP

[+GClouse]

Years ago, I did a bit of orienteering and I learned something rather quickly. Just knowing which direction you want to go may not get you there. You have to be able to work out the best route to the destination.

 

At the first orienteering meet I attended, this point became painfully obvious to the first team to start.

They were issued the map, which had 20ft contour intervals. They oriented the map, found the heading toward the first marker flag and took off running. At the end of the motel parking lot where we started, the both leaped over the hedge.... and off a 14-foot bluff. The second team stopped at the hedge and started laughing. I was on the third team. Fortunately for team #1, the motel groundskeeper had been dumping the grass clippings and leaves and such off the bluff so the guys only got a bit scratched up.

 

Just following the arrow may run you into a rock wall, or a cliff, or some other obstacle. If you have basic map skills and a map, you can work out the best route. Even then, you may need to change your approach while you are out there.

 

BTW My preferred compass is an old boyscout-issued Silva.