Take Me To GPS School

[iAmKrzys]

[...] So we essentially abandoned the GPS field portion of the course, leaving that section to introductory GPS concepts only, with exercises left to the student to learn by them selves, incorporating what we taught them in the basic field course. We felt we really needed to use the time available to get the students as proficient as possible in more traditional basic land navigation skills, and they could then better learn their specific GPS applications on their own. [...]

I sure hope that the people in the course actually did some gps homework afterwards. I highly recommend this story of a plane crash near Lake Placid few years ago ( http://www.adirondackdailyenterprise.com/page/content.detail/id/535748/Pilot-calls-surviving-plane-crash--divine-intervention-.html?nav=5046 ) in which the rescue got delayed because of "coordinates mix-up." While in the end everyone involved made it out all right, understanding gps basics can make a huge difference in rescue effort. Here is a relevant excerpt from the article:

The men were told a search party would rescue them. Using a GPS, the men provided the dispatcher with their coordinates in a formula that uses degrees, minutes and decimals of minutes.

That formula is slightly different from the formula local emergency responders normally use, DEC spokesman Dave Winchell said. Forest rangers and other emergency personal usually use a degrees and decimals of degrees formula, so when the coordinates were relayed by the dispatcher to forest rangers and state police, there was a mix-up.

 

[DougPaul]

I haven't made my mind up 100% but pretty close. I'm most likely going to keep the unit and learn it! Similar along the lines of DougPaul's comments, I don't see why any paper map user (ME!!) would have any negative sentiments toward the use of GPS. It's an additional tool. I really like the fact this unit gives me lots of data I enjoy knowing like altitude, time to next marker, total time expended, and a ton of customization options for your dash board.

I regard the paper map as being complementary to the GPS map. The screen on a portable GPS is very small and can only show a very small area with good detail or a large area with very little detail. By using the paper map to cover the larger area at decent detail (good for situational awareness and route planning) and the zoomed-in GPS display to show the local area (with an indication of my exact location), I get the best of both worlds.

By working in this way one can also transfer one's location from the GPS to the paper map by inspection (ie no need to read off and interpret the lat-lon numbers).

Doug

 

[DougPaul]

Yea.... Ask the Pilgrims..they made it..they were only 700 miles or so off.

Going to sea was pretty dangerous. Nautical navigators became very good at skills such as dead reckoning--but they still paid in broken boats and lost lives when conditions were less than ideal.

Going to sea still has its risks, but due to electronic methods of navigation not knowing one's location is no longer one of them...

Doug

 

[DougPaul]

We felt we really needed to use the time available to get the students as proficient as possible in more traditional basic land navigation skills, and they could then better learn their specific GPS applications on their own. So that is how the formal course is structured today.

A GPS receiver basically automates many traditional (eg map and compass) navigation techniques plus it "knows" your current location very accurately. Thus if one already knows the traditional techniques it can be very easy to learn how to do them with a GPS (and you don't even have to bring a chart table, parallel rules, dividers, etc along with you ).

Much of the complexity of using a GPS is in the bells and whistles and user interface. (And, of course, such details vary with the model and manufacturer.)

Doug

 

[DougPaul]

Just remember the Altitude in GPS's are not as accurate as the horizontal data is.

The average horizontal accuracy of a typical consumer GPS is around (95% probability of being within) 10 meters and the average vertical (GPS altitude) accuracy is on the order of 20 meters.* However, the accuracies at any specific moment depend on a number of factors including the satellite constellation. (Don't forget that maps also have errors which can be larger than the GPS errors. So don't panic if your GPS shows some feature to be in a different location than your map...)

* Vertical and horizontal accuracies would be similar if the earth weren't blocking signals from below the user...

The core GPS actually outputs a 7-dimensional vector (3 dimensions of location, 3 dimensions of velocity, and 1 dimension of time) once per second. The the altitude parameter has a fairly large short-term variation but has a pretty good long term average accuracy. A barometric altimeter has good short-term accuracy but poor long-term accuracy. Using the GPS altitude to continuously calibrate a barometric altimeter gives the best of both worlds--good accuracy after sufficient time for the calibration to settle down. Such automatic calibration automatically compensates for both user movement and changes in the [sea level equivalent] barometric pressure.

In practice, I leave automatic calibration on all the time and just make sure I turn the GPS on an hour or so before hitting the trail to allow the calibration to settle down**. When I reach surveyed altitude locations such as summits, the GPS generally reads within 10 ft of the published altitude. (The spec for my Garmin 60CSx is "accuracy, +/- 10 feet, subject to proper user calibration".)

** If I am unable to run the GPS ahead of time I simply bear in mind that the initial vertical accuracy may be poor, but will improve with time.

You can calibrate your barometric sensor from a known altitude or the sea level equivalent pressure, but IMO there is no advantage for typical hiking usage. Automatic calibraion also saves time and if the situation becomes tense, it is one less thing to worry about.

Doug

 

[DougPaul]

I sure hope that the people in the course actually did some gps homework afterwards. I highly recommend this story of a plane crash near Lake Placid few years ago ( http://www.adirondackdailyenterprise.com/page/content.detail/id/535748/Pilot-calls-surviving-plane-crash--divine-intervention-.html?nav=5046 ) in which the rescue got delayed because of "coordinates mix-up." While in the end everyone involved made it out all right, understanding gps basics can make a huge difference in rescue effort. Here is a relevant excerpt from the article:

The men were told a search party would rescue them. Using a GPS, the men provided the dispatcher with their coordinates in a formula that uses degrees, minutes and decimals of minutes.

That formula is slightly different from the formula local emergency responders normally use, DEC spokesman Dave Winchell said. Forest rangers and other emergency personal usually use a degrees and decimals of degrees formula, so when the coordinates were relayed by the dispatcher to forest rangers and state police, there was a mix-up.

Not only can there be differences the numerical representation of the lat and lon (typ DMS-based (degrees-minutes-seconds) or UTM), there are a number of datums (reference frames: typ WGS84, NAD83 or NAD27) to choose from...

An organization should choose a representation format and datum for internal use to prevent confusion. However any interface between different organizations (eg 911 emergency dispatchers...) should be able to accept any lat-lon format and datum and convert it to an appropriate format for internal use.

There are web based converters (eg http://www.synnatschke.de/geo-tools/coordinate-converter.php), converter programs, and the representation format and datum are user-settable on my Garmin GPSes (presumably other manufacturers as well). IMO, such converters should be built into the dispatchers' consoles and dispatchers should be instructed in dealing with the issue.

Doug

 

[CaptCaper]

Like I said many fight GPS over the years and have stuck to the "old map and compass" probably retarding any progress in the rescue field and organization upgrades. These organizations could or should of had this down pat by now. I have it down pat and years ahead of them and I'm just a no body.But it takes work to do this and constant practice to keep up with it. Is this government at it's finest? I know the USPS is 10 yrs behind UPS..
Garmin has defaults in it's settings and rescue or whomever should know what they are for one. I broke down on 93 one night and called for a tow truck. I gave my coordinates to the gal but they didn't know how to use them. So we had to deal with other ways.

 

[Nessmuk]

Like I said many fight GPS over the years and have stuck to the "old map and compass" probably retarding any progress in the rescue field and organization upgrades. These organizations could or should of had this down pat by now. I have it down pat and years ahead of them and I'm just a no body.But it takes work to do this and constant practice to keep up with it. Is this government at it's finest?

I don't know where you are coming from, but in NY the DEC Rangers have had formal training for organized SAR teams for quite a few years. There isn't a viable SAR team that I know of (there are 26 such teams in NY State) that doesn't operate using both map and compass and GPS devices for their trained team members.

During a SAR incident each field team will have a trained Crew Boss leader. You can't become certified as a Crew Boss without going through a fairly intensive 2-day qualification session (this is not a training session). The CB candidate must demonstrate a high level of proficiency in plotting and use of map and compass without error on a woodland field course, and then do the same using a GPS. Prior familiarity with map and compass, and integration with a well practiced GPS is mandatory.

DEC Rangers, Crew Bosses and other knowledgeable individuals regularly offer multi-day land navigation training courses that stress the importance of map and compass competency along with use of the GPS in the field. I for one have my own 2-day training course in basic and advanced land nav. Only after I am satisfied that my students understand traditional navigation methodology and procedures do I then instruct a half day course using the GPS.

During actual SAR incidents the CB is responsible for leading his/her assembled crew of the day to their assigned search block as plotted on a topo map, and in keeping a continuous track log of the day's accomplished grid search pattern. Understanding the terrain from visually interpreting the topo map and observational navigation of the landscape with map and compass, while accomplishing the precision search pattern are just as important as use of the GPS tool for determining point locations and recording the track, and calling in coordinates of clue or subject finds back to the IC. The track log at the end of the day is downloaded to the DEC Rangers' computer system at Incident Command, as well as the CB's visual account of terrain layout and hazards at a formal debriefing. This all goes into the formal planning of the next day's mission tactics.

So please explain to me how being "stuck to the old map and compass is probably retarding any progress in the rescue field and organization upgrades"?

 

[CaptCaper]

I don't know where you are coming from, but in NY the DEC Rangers have had formal training for organized SAR teams for quite a few years. There isn't a viable SAR team that I know of (there are 26 such teams in NY State) that doesn't operate using both map and compass and GPS devices for their trained team members.

During a SAR incident each field team will have a trained Crew Boss leader. You can't become certified as a Crew Boss without going through a fairly intensive 2-day qualification session (this is not a training session). The CB candidate must demonstrate a high level of proficiency in plotting and use of map and compass without error on a woodland field course, and then do the same using a GPS. Prior familiarity with map and compass, and integration with a well practiced GPS is mandatory.

DEC Rangers, Crew Bosses and other knowledgeable individuals regularly offer multi-day land navigation training courses that stress the importance of map and compass competency along with use of the GPS in the field. I for one have my own 2-day training course in basic and advanced land nav. Only after I am satisfied that my students understand traditional navigation methodology and procedures do I then instruct a half day course using the GPS.

During actual SAR incidents the CB is responsible for leading his/her assembled crew of the day to their assigned search block as plotted on a topo map, and in keeping a continuous track log of the day's accomplished grid search pattern. Understanding the terrain from visually interpreting the topo map and observational navigation of the landscape with map and compass, while accomplishing the precision search pattern are just as important as use of the GPS tool for determining point locations and recording the track, and calling in coordinates of clue or subject finds back to the IC. The track log at the end of the day is downloaded to the DEC Rangers' computer system at Incident Command, as well as the CB's visual account of terrain layout and hazards at a formal debriefing. This all goes into the formal planning of the next day's mission tactics.

So please explain to me how being "stuck to the old map and compass is probably retarding any progress in the rescue field and organization upgrades"?

Well your DEC Rangers seem to have it in order.... As posted above that unit got all mixed up. Or maybe every organization now is on top of all of this. I am not an expert on all organizations and their agendas. I just hope there is a CB on duty if I ever need assistance.

Hopefully the OP head is not spinning too much and is reading all of these posts.. as this is just the beginning for him.

 

[Nessmuk]

Well your DEC Rangers seem to have it in order.... As posted above that unit got all mixed up. Or maybe every organization now is on top of all of this. I am not an expert on all organizations and their agendas. I just hope there is a CB on duty if I ever need assistance.

Admittedly the confusion surrounding the location of the airplane mishap near Lake Placid was a misunderstanding between what the dispatcher understood as location coordinates and passing of that information to Rangers in the field. It is a lesson learned point well taken, to ensure that coordinates are understood to be either in DD.ddd or DMS format. That case example has been part of every Land Nav course I have been involved with since the incident happened, so hopefully it will not ever happen again.

Actually in the field UTM is used almost exclusively rather than Lat/Lon, except when communicating with aircraft, since they are flying Lat/Lon by default. There is a nationwide push on to switch over to USNG format, but that is only a small format change from UTM, with little chance for confusion after a brief introduction to USNG. The only other possible point of confusion is the datum. Some regions prefer WGS84, since that seems to be the digital default, while others still use NAD27 since that is the format of most existing USGS topo maps. The morning SAR IC briefings will always state which format to use when transmitting location information. Conversion from any of the coordinate or datum formats to any other is easy to do within the GPS, as long as the input is done correctly.

 

[iAmKrzys]

Here is a practical tip involving coordinate format conversion from ddd.ddddd to ddd mm.mmm that everyone who wants to ease the pain of getting to traihead parking can use.

First a tiny bit of simple math (I assume everyone still remembers how to do proportions):

Since 1 degree = 60 minutes, we can calculate Minutes = Degrees * 60. Simple, right?

In practice you will want to apply this to fractional part of degrees to keep the number of minutes under 60 because that's what your gps wants. To keep conversion error down to few feet you should retain 5 significant digits of fractional part of degrees.

Now, let's say that you go to Google maps, look at satellite images and see where the traihead parking is e.g. you do a "pin drop" for Crawford Path connector parking entrance https://www.google.com/maps/place/4...3787,582m/data=!3m2!1e3!4b1!4m2!3m1!1s0x0:0x0 and you get this in browser address box:

www dot google dot com/maps/place/44%C2%B013'21.9%22N+71%C2%B024'40.3%22W/@44.2227668,-71.4133787,582m/data=!3m2!1e3!4b1!4m2!3m1!1s0x0:0x0

The key part of this web address is "44.2227668,-71.4133787" which represents 44.2227668 degrees North and 71.4133787 degrees West (the "-" in front of "-71.4133787" means West.)

First, we take fractional portion of 44.2227668 and multiply by 60:

North Minutes (without whole degrees) = .2227668 * 60 = 13.366

and similarly for West coordinates we take fractional portion of -71.4133787 and get

West Minutes (without whole degrees) = .4133787 * 60 = 24.803 (with rounding)

Putting everything together we get coordinates that most Garmin car GPSes can understand (some have option to enter coordinates while others will accept it via "Search" box):

N 44 13.366 W 71 24.803

To check sanity of your calculation you can copy this into Google maps and check what it shows you, although Google maps will often move the pin drop to nearby road. Also, always check what your car gps will show you before you start driving - if you mistype a digit it can take you miles away from your intended destination! On the other hand if you use coordinates then the trailhead parking does not need to have a street address for your gps to find it.

Obviously once you understand this calculation you can save yourself some time and use the conversion tool that DougPaul posted: http://www.synnatschke.de/geo-tools/coordinate-converter.php but you can do the conversion any time without Internet access as long as you remember what to do, or reason through "1 degree = 60 minutes".

Good luck and let me know if you have any questions on this.

 

[iAmKrzys]

www dot google dot com/maps/place/44%C2%B013'21.9%22N+71%C2%B024'40.3%22W/@44.2227668,-71.4133787,582m/data=!3m2!1e3!4b1!4m2!3m1!1s0x0:0x0

The key part of this web address is "44.2227668,-71.4133787" which represents 44.2227668 degrees North and 71.4133787 degrees West (the "-" in front of "-71.4133787" means West.)

When I used these coordinates in OpenStreetMap I realized that these coordinates in the address bar are for the center of the map and not for the location of the marker. You can get coordinates for the marker by clicking on the link that pops up when you do the pin drop:



So let's redo this calculation now with correct coordinates: 44.222754, -71.411154

North Minutes: .222754 * 60 = 13.365
West Minutes: .411154 * 60 = 24.669

And the coordiantes to parking entrance are:
N 44 13.365 W 71 24.669 (meaning 44 degrees 13.365 minutes North and 71 degrees 24.669 minutes West)

Now if you copy N 44 13.365 W 71 24.669 into Google maps search it will show you actual entrance to the traihead parking.

Apologies for any confusion I might have caused!

 

[CaptCaper]

The OP's head must be spinning super speed..... If you the OP is still with us and haven't skipped school...check out the Position Formatting option in the Setup Menu.
You can change that to (Garmin converts) use with Google. Or any position different from any Map as Garmin will convert it so you can enter it manually or take it to something like Google Maps. Google Earth has an option under tools/options to change/convert the coordinates as well.
Garmin's default is Degrees and Decimal Minutes... which looks like this... N44 13.101 W71 24.701

Google default is Decimal Degrees which looks like this N44.21834 W71.41168

This is for Crawford Depot parking in Bretton Woods.

 

[wardsgirl]

The GPS is here!

The GPS IS HERE!!

OMG, this is going to be so much fun to play with. Hey, I wonder how I'm supposed to put the card thingy in the slot...

The directions that come with the unit are downright laughable. I'll check the online owner's manual.

And, I'd better use up those bananas soon...

 

[DougPaul]

I wonder how I'm supposed to put the card thingy in the slot...

It goes under the silvery metal plate (memory card cover) in the battery compartment.

Slide the cover plate up to unlock, pivot it open, place the memory card on the contacts, pivot the plate down (gently), and slide the cover plate down to lock. It's pretty easy to do.

Doug

 

[BISCUT]

The OP's head must be spinning super speed..... If you the OP is still with us and haven't skipped school...check out the Position Formatting option in the Setup Menu.
You can change that to (Garmin converts) use with Google. Or any position different from any Map as Garmin will convert it so you can enter it manually or take it to something like Google Maps. Google Earth has an option under tools/options to change/convert the coordinates as well.
Garmin's default is Degrees and Decimal Minutes... which looks like this... N44 13.101 W71 24.701

Google default is Decimal Degrees which looks like this N44.21834 W71.41168

This is for Crawford Depot parking in Bretton Woods.

No hookey for me sir! I've been pretty busy but appreciate the wealth of knowledge in the responses. I'm keeping mine

 

[CaptCaper]

No hookey for me sir! I've been pretty busy but appreciate the wealth of knowledge in the responses. I'm keeping mine

Just practice practice ..etc. I use mine even on small hikes like Mt Willard after work to perfect the use I like to do and to keep in shape and not forget.
On a side note if the unit ever jams up from getting it confused during the learning curve you have to learn, just take the battery and and reinstall it will clear up...same as restarting a PC. My Montana 600 was pretty flawless and worked well or better then any GPS I've owned since 1996. At first it's over whelming with the menu setups and options compared to smaller GPS's but once you set a profile you will find it's the Cat's Meow. Also I carry mine in an external pouch with a Gilsson small antenna on the top of the pack but you can get good results carrying it in a Gizzmovest case on the pack etc. as well.
Her is a link to help with the use/setup etc of it...

http://garminmontanagpsr.wikispaces.com/Features

 

[LavaFalls]

perfectly said

I have commented many times on this topic, here and elsewhere. I will only say that the GPS can be both a tool and a toy, depending on how it is used and requirements for use. Just understand that navigation is a multi-element system process. Some want to learn to navigate as a prime experience in itself, when time honored methods are best for the purpose and result in the greatest satisfaction in the desired experience. Others just want to get from point A to point B with minimal effort, when using the most advanced electronic tool is best to accomplish the JOB at hand (think surveying and SAR, to name only two). Understanding the basic tenants of navigation, which most definitely includes using the most advanced tool that resides between your ears along with your eyes is always a fundamental basis for navigation. The process (think tools or toys as separate functions) can be supplemented with all available electronic knowledge sources, is what you may then decide to use. Observational navigation (eyes and brains) with available map and compass goes without saying as necessary for all navigators, regardless of other assists. Want to add GPS, then go ahead. Just please don't depend on any method that does not include how to get out of situations without using the gray matter as the ultimate educated resource.

NussMuk:
You nailed perfectly...use that "gray matter" as the ultimate educated resource. Too many out there are forgetting the gray matter and relying on a toy/tool to make their decisions. Go Safe...go Easy.
LavaFalls

 

[CaptCaper]

NussMuk:
You nailed perfectly...use that "gray matter" as the ultimate educated resource. Too many out there are forgetting the gray matter and relying on a toy/tool to make their decisions. Go Safe...go Easy.
LavaFalls

Sorry to disagree... as a Master Captain licensed with the USCG and a expert at navigation I can tell you it's not a toy....what is your experience with a gps? Please don't refer it to a toy. It's a tool period. You just put doubt or insecurity into others trying to grab hold of making a hike safer and more enjoyable.
And like tools many don't know or don't care on how or why to use them. And many do. There are many folks who just don't or can't figure out how to use maps and compasses either. Matter of fact it takes a lot of grey matter to learn and use a gps proficiently as well. So who's lacking grey matter here.
Like I posted above and for many years against posts claiming it's a toy... there are many hikers today that would be alive if they had a gps..some times maps and compasses can't cut it. This goes for Mariners who didn't have any EPIRB's as well.

 

[wardsgirl]

It goes under the silvery metal plate (memory card cover) in the battery compartment.

Slide the cover plate up to unlock, pivot it open, place the memory card on the contacts, pivot the plate down (gently), and slide the cover plate down to lock. It's pretty easy to do.

Doug

Thanks!

I just grabbed the pdf that Trail Boss linked and I see that there's also a 'unlock toggle' step (step 3). I am not mechanically inclined, so I missed that.

You can install a microSD memory card in the handheld device for additional storage or pre-loaded maps.
1 Turn the D-ring counter-clockwise, and pull up to remove the cover.
2 Remove the battery.
3 Slide the card holder to unlock and lift up.
4 Place the memory card with the gold contacts facing down.
5 Close the card holder.
6 Slide the card holder to to lock it.
7 Replace the battery and cover.


This GPS will be cool to use for trailwork if I can figure it out. When I'm in the middle of evaluating drainage on featureless trails like the Davis Path, one waterbar looks like the next. I'm thinking it will be awesome to know how far it is to get back to my car or a dunk in the Saco on a hot day.