GPS is the magic bullet. You press a button and you get a position. Press another and it gives you a course, cross-track error, even a chart or an airphoto. What navigator wouldn’t want that? On the other hand, plotting a fix is only the beginning of the navigational process. Whether generated by electronics, triangulation from bearings, aids to navigation, or celestial observations, the fix is not the end of the process, it’s where it begins. What follows is where the navigator earns his pay.

First, the position is interpreted in relation to the existing dead reckoning track:
how close, or how far off, is it? This immediately makes the mariner aware of the effect of conditions on the motion of his vessel, as well as the accuracy of his methods. As the new DR track is layed out, the immediate future of the ship is predicted; on the chart is a visual description even a non-navigator can understand where and when hazards can be expected, or if, when and where new opportunities for verifying the position can be expected to materialize. What navigator has not felt the thrill of seeing a light pop up over the horizon, right on schedule, justifying the previous night’s fix and dead reckoning. It’s a terrific feeling, isn’t it?

Then there’s the feeling you get when the light or other ATON you expected is not there. Is your navigation off? Did an unexpected current affect your course, could the light be out of service? Until you determine why, you are aware that your ship is potentially standing into danger, and you know you have to get to the bottom of it, it is your job, your responsibility. A lifetime of situations like this builds up a deep intuition, a reservoir of memory and skill we can draw on and which defines the true mariner. How often have you not made an observation, or written down a result, and a little voice in the back of your head tells you “Wait a minute. That doesn’t seem right, something’s wrong.” Psychologists tell us that a great deal of mental processing occurs subconsciously, without our being aware of it, but it is mental activity nonetheless. You can call it intuition, judgement, or experience, but you can only get it one way: on watch.

You don’t get that feeling with electronics, and you don’t develop that kind of subconscious skill.
You press a button and get a position. The machines are reliable and you can have confidence in their accuracy, but what happens when they don’t work due to malfunction, operator error, or battle damage? Panic, disorientation, confusion; because the operator has no other skills and resources, no experience to draw on. Even when the equipment is working perfectly, operators sometimes lose confidence in its operation and make a panicky decision leading to disaster. Aviators are trained to “trust their instruments”, but they can become disoriented too. GPS-assisted groundings are now as common as radar-assisted collisions.

No one denies the usefulness of electronic aids to navigation, but the danger in their use arises from the fact that the skills of the navigator are neglected. Instead, the operator expends his time and effort and professional comittment on operating the equipment and mastering it’s many bells and whistles, or in learning new versions and user interfaces, all of which seem to change almost on a daily basis. It seems that the best feature of modern navigation technology, its ease of operation, has now been perverted so that navigating through the menus and typing in cryptic commands is harder than using a sextant and reducing a sight. And of course, after you learn it all, it becomes obsolete in about six months. The hardware and software is often highly customizable, so even expertise with a specific system can mean a steep learning curve when you are faced with identical gear somewhere else. You get so busy “managing” the technology that sometimes you forget to look out the bridge windows.

One of the skills a navigator develops is a healthy skepticism for his sources of information. Charts have errors, so do pubs. You are attuned to math mistakes and observational errors, you are aware how easy it is to misunderstand a shipmate under stressful conditions. Over the centuries, navigators have developed procedures and methods to minimize these problems, and a critical attitude to help them evaluate and verify the accuracy of the information they use. This is not the case with electronics, and especially with software. What appears on the screen or comes out of the printer does so with an air of legitimacy that makes it easy to forget that if garbage goes in to a system, then only garbage will come out. The gear may be foolproof, but the data it operates on is the same data we use with traditional methods. There are still charts in the inventory that were based on original surveys by Capt. Cook over two hundred years ago. They’re actually pretty good charts, and certainly better than nothing, but if you’re using one you are well aware of its history, its value and its limitations, and you rely on that unconscious judgement, your mariner’s intuition, when you plot your fixes and take your bearings. Your whiz-bang graphical GPS electronic charting system may be drawing your course on that same chart, but its flawless appearance on the monitor screen does not alert the machine operator to the potential dangers of data compiled centuries ago. A true navigator would know that instinctively.

So what are we doing about it? As the machinery becomes more effective and more complex to use and maintain, do we train machine technicians to learn navigation? Or are we better off training our navigators to learn systems operation. The US Navy has already made that decision. Let’s hope that they keep a log so that down the line, if it’s the wrong one, we’ll have the evidence to correct the error. And let’s hope its a Quartermaster who keeps that log, not a programmer.

National Geographic’s maps used USGS maps in an excellent viewer called “TOPO!”. They used to come on CD’s, with a state like Colorado on several disks. They migrated to DVD’s with entire states. I have several of these and they are invaluable to my work. TOPO! became AllTrails (http://alltrails.com/) which is a cloud based service. A guy I work with uses this service but I still use the DVD’s.

Magellan units of that era also used the Vantage Point software. Did you get that with the unit? As I recall, it had some useful measuring tools.

Do you have the original plat map? If so, you should be able to take the bearing of that property edge, and use your GPS to stay on that bearing until you get to the tree. Lots of error in that method.

Try a search with your county name and GIS. Many counties now have excellent GIS viewers with air photos of greater detail than google maps. Some viewers link to original plats, but if not, you can always get the book and page number of your property and obtain that plat from your county at a small fee. Some have data for download but typically those are shape files for GIS programs. (If Google Maps has parcel info, they got it from your county’s GIS site) Free viewers are often available. Sometimes, the data is available for Google Earth (.kmz, .kml).

It acquired satellites in about 20 seconds.

My biggest gripe about the Magellan was the map. It was very basic, only containing major highways and roads. One of the original selling points was you could download topo maps from National Geographic. As far as I can tell, they’re no longer available.

I assume it’s the same with all manufacturers, but Magellan sells detailed maps you can download. $150 for continental US or $50 each of 4 US “regions”. What a racket…

As an aside, I have a 20yr old friend who lamented he has a poor sense of direction. I don’t think he’s ever been without a smart phone and uses the internet to get directions. He doesn’t understand the value of landmarks.

I told him he needs to study maps of our entire area to learn his place in his surroundings. He informed me that most of his generation can’t read an analog watch.

In my opinon they’ve been denied a richer life experience by not knowing where they are at any given point in time.

Now it seems to me that cottonwood trees are very short-lived, rot rapidly and are hazards, dead or alive, in stormy conditions. A 150′ cottonwood would be especially dangerous, and most people would consider it a public service to drop that sucker. Or cut off the top half, which might render it harmless and open your viewing.

The det cord is an idea, maybe not a good one. The stuff is terrifying, I think because there’s no control over it. You don’t watch det cord, it’s an event, it just happens. People got good with it with practice, I was curious, not that curious.

It’s a good thing the NRA hasn’t found a way to see that det cord and plastic explosives aren’t available at your local Toys ‘R’ Us.

My suggestion is to wrap the tree a few times, at a nice angle to help direct the fall, and associate it with a detonator and/or a “much slower” fuse.

Det-cord was a plastic explosive designed to be used as an instant fuse. It has a very fast rate of burn. If you were to loosely wrap one end around your ankle and had someone else — **even half a mile away** — ignite the other end, there is no way you could avoid losing the foot. There would not be enough time to even step out of the loop.

Det-cord = very nasty stuff

via Gizmodo.com