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Is GPS All in Our Heads?
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Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: gps + sustainable earth frienddly? I don't think so on 02/09/2012 16:17:33 MST Print View

Global Positioning System is a U.S.-funded system.

Europe has Galileo, which is government funded as well.

GPS is not Galileo.

Each of these systems have different services supported. Some services are military in nature, and some are purely commercial. Some services are classified.


Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: gps + sustainable earth frienddly? I don't think so on 06/20/2013 18:59:07 MDT Print View

"It's also a government system."

Galileo is still a _future_ government system that resembles a money sink.


Greg Mihalik
(greg23) - M

Locale: Colorado
The Lazareth GPS thread on 06/20/2013 19:05:24 MDT Print View


Did the real Bob Gross resurrect a thread that is 16 months old?

That's pretty desperate, even for Bob.

(You never know who in that cadre is really posting....)

Edited by greg23 on 06/20/2013 19:22:51 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: The Lazareth GPS thread on 06/20/2013 20:13:19 MDT Print View

I had been traveling for three weeks. When I got home, there was a telephone message from a complete stranger asking questions about GPS, and he had gotten my name here at BPL. What I did not understand was how he got my home telephone number. So, I thought that I would post something innocuous here on the GPS topic, and maybe he will pop up again.

Mostly it is just federal employees who call in the middle of the night asking GPS questions.


jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: The Lazareth GPS thread on 06/20/2013 20:44:43 MDT Print View

The NSA has your telephone number

And a record of all your calls

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Re: The Lazarus GPS thread on 06/20/2013 20:50:40 MDT Print View

>Did the real Bob Gross resurrect a thread that is 16 months old?

The real Bob Gross can post about GPS whenever he wants.

Just like "Chuck Norris does not sleep. He waits.", the real Bob Gross doesn't need an antenna, he IS an antenna.

Brian Lewis
(brianle) - F

Locale: Pacific NW
GPS as nav learning tool on 06/20/2013 21:01:08 MDT Print View

Back to the original topic ...

I don't think anyone has yet mentioned that a GPS can be useful for at least some people as an *aid* to learning land navigation. For one thing, it can be pretty helpful to determine and/or confirm that you're at a particular spot, just to give solid feedback on what you're doing. A mapping GPS can help a person learn the relationship between a map image and what's on the ground.

While I agree with the concern that we can rely too much on GPS and lose (or never gain in the first place) solid map skills, I think it's worth pointing out how helpful the device can be in establishing those skills too.

It's somewhat reminiscent of the debate some years ago about how the spread of electronic calculators would result in future generations of kids who can't do basic math. While I'm not certain, it appears to me that particular issue is being resolved by nearly universal availability of calculating power, and indeed less or no pervasive skill at things like long division.

In the same way, the GPS is clearly here to stay; we should push for folks to learn solid map reading skills above and beyond "how to use a GPS app", but don't pretend or hope that GPS isn't a tool that they'll use, and leverage the device for what it's good for as a teaching tool.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: The Lazareth GPS thread on 06/20/2013 21:01:15 MDT Print View

"The NSA has your telephone number"

Actually, it is an NSA guy who used to call me in the middle of the night asking some GPS question.

I knew that he worked for NSA, but he would never verbally reveal that he worked there.


David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Old and new on 06/21/2013 00:30:20 MDT Print View


I'll readily agree that GPS is here to stay and, like magnetic compasses, sharp edges, and clothing; we're not going back.

Here's a last-generation example of the useful of a "non-essential" technology. In my first decade of backpacking, there were times when I'd be sure that the campsite was just over the next rise. And then just over the NEXT rise. And AGAIN, over the NEXT one. It was exhausting. Having a Thommen altimeter solved all of that. If the campsite was at 9,400', I knew exactly how much hiking I had to do up that slope and I paced yourself accordingly. Did I "need" that technology? No, not on most days. But the added 2 ounces made, on balance, for a more pleasurable trip.

Did I sometimes *need* that technology? Yea, maybe. In a white out, on Pyramid Peak in Desolation Wilderness in Winter, it increased our safety A LOT to know exactly when to cut over to the next drainage while avoiding the steepest terrain.

That said, I'll pit my 13-year-old son (without paper or pencil) against you any day in multiplication, division, algebra, trig, calculus, or number theory; you with or without your slide rule. Just because we don't HAVE to have older skills, doesn't mean we can't and there are sometimes advantages to doing so.

Pete Staehling
(staehpj1) - F
Just another tool on 06/21/2013 08:41:48 MDT Print View

GPS is just another tool. I figure that it is worth taking and using when the smart phone is going any way or when it is lighter than the maps and guide books it replaces.

If you are somewhere that you should have back up navigation system you probably should a backup with paper maps and a compass too. Maps can be lost or blow away. I think we are very close to the point where the GPS can be as reliable as a paper map.

Personally I have usually left the handheld GPS at home and used paper maps on most trips, but as I become more comfortable with the functionality and reliability of my smart phone I am more and more likely to use it. That comfort has been growing as I have been logging my daily trail runs with MapMyRun on my android phone

I plan to use the smartphone on my next longish trip (JMT). I am still debating how much paper to take.

spelt with a t
(spelt) - F

Locale: SW/C PA
Re: Just another tool on 06/21/2013 09:28:06 MDT Print View

I wouldn't feel comfortable with a GPS if I didn't have map and compass skills. I don't care one way or the other how people rationalize their choices, but personally once I learned, maps became a lot more fun. That alone makes investing in a GPS unit unappealing.

David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Multipurposing on 06/21/2013 10:02:54 MDT Print View

> I plan to use the smartphone on my next longish trip (JMT). I am still debating how much paper to take.

Pete: Clearly (GPS or not), someone needs to print the JMT, PCT, and AT maps on toilet paper at a scale of 1 sheet per mile. 20 miles per day = 20 sheets per day. There could be larger and smaller scales for faster and slower hikers.

> I wouldn't feel comfortable with a GPS if I didn't have map and compass skills.

I feel that way about electronic calculators. If you can't use a slide rule, you have no business in science or engineering. I mean, what if a EMP comes through and fries all circuits? Now removing tongue from cheek.

Rob E

Locale: Canada
Navigation is a skill not a tool on 06/21/2013 10:27:05 MDT Print View

A compass can be lost or damaged. The declination can be set incorrectly, or even inadvertently changed while being used*. A piece of sand/grit/dirt can get stuck in the bezel and the compass might no longer rotate properly*. You can be standing over a highly magnetically susceptible rock unit which will change the magnetic field and thus change the reading of the compass*.

* all have happened to me during my career as a geoscientist.

A paper map can be lost or damaged. It can also be incorrect or not updated to reflect recent changes. A hiker who finishes with a map section might follow ultralight doctrine and burn that map section at night, only to find some obstacle/injury/disaster has forced them to backtrack and now they no longer have a map. A map can be ignored: the so called 'bending the map' phenomenon when people get lost. A map might not have the necessary features to be safe: the resolution of the topographic lines might not be fine enough to indicate the upcoming dangerous rapids in a river, or to indicate the presence of an impassible vertical cliff.

An altimeter can be lost or damaged. The batteries can run out. It can be incorrectly calibrated. The user might inadvertently get the units confused and read the display incorrectly (mBars vs inHg vs feet. vs meters). Weather systems can come in and change your altitude drastically even though you haven't moved. The altimeter might not be enough information to uniquely determine your position or to provide adequate route information, "we know we're somewhere on this contour line... but not sure where along it".

A GPS can be lost or damaged. The batteries can run out. It can be set to the wrong map datum/geoid. It might not work well in some terrains. A critical waypoint might be incorrectly entered by the user. The GPS satellite constellation may be damaged or disabled.

A smart phone can be lost or damaged. The batteries can run out. Without network coverage the user might have not downloaded the maps they thought they had, so now they only have their lat/lon, but no maps. The smart phone might only give coordinates in lat/lon, but you have a paper map with only a UTM grid (or vice versa).

Your Loran-C/VLF radio beacon navigation device can be lost or damaged. There might be a magnetic storm that prevents it from operating correctly. The network of radio beacons could be disabled. The government pulls the plug on the Loran network (or have they already?).

A sextant can be lost or damaged. Your chronometer might not be set correctly. You might misread the verner scale. The stars/sun/moon might not be visible. You lose or misplace your almanacs/tables. You might have no idea how to use a sextant.

Folksly wood-lore might be forgotten or misapplied. The moss might grow on both sides of a tree. You are in a valley and couldn’t discern the direction that the sun had set. You are in overcast skies with completely flat light, there are no shadows, and you cannot determine the direction of the sun or moon. You are at a hydrological divide, so aren’t sure if a river system drains to the Hudson Bay, or the Mississippi.

Navigation is a skill, not a tool. The whole debate of one which navigational tool/aid is universally better in absolutely every scenario than another is just like any other heated BPL debate: windshirts, rain paints, down vs. synthetic insulation, TP vs. rocks, knife vs. scissors, sawyer vs. steripen.

Now, I will throw in my two cents and say that I sometimes carry a map and compass, a GPS, both, or neither, depending on the trip.

Call me reckless, but since I once briefly inhaled campfire smoke as a child I’m not long for this Earth anyway.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Navigation is a skill not a tool on 06/21/2013 14:27:42 MDT Print View

I agree navigation is a skill, but for most people venturing into unfamiliar territory, it's a skill that depends on one tool or another, whether it be a map & compass or electronic gizmo. As any tool can fail, so it's prudent to have a backup system.
But, navigation is a skill and skills needs practice, so you must practice with both you primary and backup tools so you are proficient in both.

I quite proficient with a map & compass, but I have to admit that a GPS can save a lot of time and anxiety in a whiteout.

Mark Regalia
(markr) - MLife

Locale: Santa Cruz
Mixed Feelings about GPS on 06/21/2013 16:34:46 MDT Print View

I hike in the Sierra Nevada. Mostly it is so open and vertically differentiated that you can get along fine with a compass and map. Heck, I seldom use a compass. I don't think I will carry a GPS anymore.

I could see the value of a GPS for bushwhacking, especially in forested or very brushy country. We got lost once in a very brushy section of the Siskiyous going cross country in fog that was so heavy we couldn't see very far ahead. A GPS would have been very nice.

When I was a forester in the Sierra and needed to know exactly where I was so I could map out my plots so that people could find them later I dreamed of something like a GPS. They didn't have them then. My buddies who stayed in the field now use them routinely.

I do think that they are much better than maps in cars when you don't have a a navigator with you. But you have to do your homework before starting. I kind of memorize the map so if the GPS sends me way wrong, which it has, I will hopefully catch on to it and re-navigate. I have also used it when I took a wrong turn. It can find me a way back.

Rob E

Locale: Canada
Re: Mixed Feelings about GPS on 06/21/2013 18:18:25 MDT Print View

" ... so if the GPS sends me way wrong, which it has, I will hopefully catch on to it and re-navigate."

Although "GPS" is named a "positioning system", it really is just an accurate timing system. "Global timing system" would be a more apt name. GPS receivers, through a variety of clever techniques, determine the amount of time it takes for several signals transmitted from low orbiting satellites to propagate to your antenna, to within 10s of nanoseconds. GPSs don't "measure" position, they measure time differences. As a consequence of measuring time differences, position can be calculated*.

Why is this important to the discussion? Because "GPS" only measures propagation time of signals. Everything else is calculated. "GPS" isn't a car icon on a street map with soothing voice instructions to turn and follow a route. That is entirely a computer program. "GPS" isn't a handheld computer with a color display that shows your location plotted on a map with a track and waypoints. That is entirely a little handheld computer and a computer program.

In your example, "GPS" didn't send you the wrong way. A GPS receiver measured timing information of signals from space to within a few 10s of nanoseconds, and from this, it calculated your position accurately while you were travelling at a fairly high velocity. This in itself is a pretty awesome technological feat.

A computer program with a database of street map information, running on a small form factor computer with a little LCD display sent you the wrong way. GPS had nothing to do with it, except provide your location. Your location could have been provided by any number of ways: you could have input it directly, it could have attempted to triangulate your position from the stars, radio beacons, or from wifi networks (as apple ipod touchs do for example).

So, why the rant? This whole thread started with an article that GPS is making us dumber and that we cannot make mental maps, and that future generations are doomed. I just want to get it clear: measuring signals from space accurately within a few nanoseconds isn't a problem. Trusting little handheld computers running crappy software that attempt to read your mind and tell you where to go is the problem. GPS is great.

Saying that GPS sucks because the voice on your Tom Tom sent you the wrong way is like saying that magnetic navigation sucks in 200A.D. because paper maps didn't exist.

* I am not, and do not claim to be, a GPS expert. I am at best, a learned amateur. And am versed in PRN codes, how GPS timing is determined, and have written a couple of computer algorithms to turn pseudoranges into ECEF Earth-Centered-Earth-Fixed coordinates, and then into lat/lon positions, have done some dabbling in ionospheric/tropospheric correction terms, and have manually post-corrected said calculations with updated satellite ephemeris. As I said, not an expert, and I look forward to B.G. et al. correcting me for any discrepancies I may have made.

Edited by eatSleepFish on 06/21/2013 19:57:51 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Mixed Feelings about GPS on 06/21/2013 19:08:45 MDT Print View

Although the term "triangulate" is understood by most, technically a better term would be "trilaterate," even though that is a tough word. A GPS receiver measures tiny increments of time, or the length of sides of various triangles, and it does not measure the angles.

Agreed, the basic principles of a GPS receiver work great. It is only when you start piling on the mapping functions, auto-routing functions, and fancy software that you start getting into trouble.

Once you understand how to measure nanoseconds of time based upon atomic clocks, you will likely quit wearing a normal wristwatch.


David Thomas
(DavidinKenai) - MLife

Locale: North Woods. Far North.
Nanoseconds. And other units. on 06/21/2013 19:27:22 MDT Print View

A light-nanosecond is a foot. (30 cm in Australia.)

There are 3+pi/4 liters in a gallon.

Water in a pipe or stream travels at 5 feet per second.

An ostrich egg makes an omelet for one dozen people.

Okay, those are all approximations. But very useful ones.

Stuart R
(Scunnered) - F

Locale: Scotland
Re: Nanoseconds. And other units. on 06/22/2013 03:13:21 MDT Print View

"A light-nanosecond is a foot"

In other words, the speed of light is (about) one foot per nanosecond.
Electronic signals travel at much the same speed. So, if you have a 1GHz signal travelling along a wire, the voltage level will change every 15cm. If you look at a PC motherboard, you may notice that many tracks do not take the shortest route. This so that related signals travel the same distance and so arrive in phase.

My favourite unit of time is the nano-fortnight, as in "I'll just be along in a nano-fortnight".