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Help With Projecting Waypoints

#1 User is offline   swala 

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Posted 31 October 2005 - 02:29 PM

I have a 60 CS and would like to find a cache that requires projecting a waypoint from posted coordinates. I have no clue how to do this. Can anyone help me out?

Thanks

#2 User is offline   Sputnik 57 

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Posted 31 October 2005 - 02:32 PM

Sure. Take a look at question 8 of the Waypoints Section of the FAQ.

Edit: Oops, question 8, not 6.

This post has been edited by Sputnik 57: 31 October 2005 - 02:33 PM


#3 User is offline   Quoddy 

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Posted 31 October 2005 - 03:49 PM

For a quick projection I do the following:

(Usually the projections are magnetic, so make sure you are set up for mag. not true)

1. Mark the spot you are at.

2. Using the compass, aim the GPSr in the direction required to match the degree angle. (I usually pick an easily identifiable spot/object)

3. Switch to the map and click "Measure Distance". From that extend the cursor out to the desired distance and click enter. This gives you a push-pin on your map.

4. Go to the push-pin spot and you will be very close. I usually recheck the distance and make it exact by hitting "goto" the beginning marked point.

Hope this helps.

#4 User is offline   jacques0 

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Posted 31 October 2005 - 07:08 PM

Quoddy, on Oct 31 2005, 03:49 PM, said:

For a quick projection I do the following:

(Usually the projections are magnetic, so make sure you are set up for mag. not true)

1. Mark the spot you are at.

2. Using the compass, aim the GPSr in the direction required to match the degree angle. (I usually pick an easily identifiable spot/object)

3. Switch to the map and click "Measure Distance". From that extend the cursor out to the desired distance and click enter. This gives you a push-pin on your map.

4. Go to the push-pin spot and you will be very close. I usually recheck the distance and make it exact by hitting "goto" the beginning marked point.

Hope this helps.

I do a variation of this. Keep in mind that as you walk AWAY FROM a marked GOTO, the gps will show a bearing that is 180 degree from your heading, and the distance to that GOTO, shown on the gps, will increase as you walk away.

So, I simply make sure my starting point is marked, then take my magnetic compass and take a bearing on the desired direction of travel, then walk in that direction. You may need to take additional bearings with the compass if the projected waypoint is a long ways off . Check the gps to determine how far you are from your starting point, and verify that the bearing to that starting point is 180 degrees different from the desired heading to your new destination. If you've been careful with the compass, you'll probably be within a few steps either side to correct the bearing. It sounds more difficult than it is. It's actually very easy. An example might be: Find a cache located 530 feet---and 227 degrees---from a starting point. If the starting point is already set as a GOTO, then just leave it. Otherwise, set it as a GOTO. Now use your compass to find something 227 degrees from the start point. As you walk toward it, the gps is now indicating the direction to your start point as 47 degrees (227 minus 180; i.e., it's behind you), and the indicated distance to the start point is increasing as you walk away from it. When you're 530 feet from the start point, and the start point is 47 degrees from you, then you're at your destination.

It's very fast doing it this way, as you don't have to enter new numbers for the projections. Just mark your current position, set it as a GOTO, and then walk away from it.

#5 User is offline   Olar 

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Posted 01 November 2005 - 03:52 AM

The 60CS has a "project waypoint" feature which makes it very simple and foolproof. It should be described in the FAQ that Sputnik 57 pointed to.

Cheers, Olar

#6 User is offline   stevesisti 

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Posted 01 November 2005 - 05:17 AM

Quoddy, on Oct 31 2005, 07:49 PM, said:

For a quick projection I do the following:

(Usually the projections are magnetic, so make sure you are set up for mag. not true)

1. Mark the spot you are at.

2. Using the compass, aim the GPSr in the direction required to match the degree angle. (I usually pick an easily identifiable spot/object)

3. Switch to the map and click "Measure Distance". From that extend the cursor out to the desired distance and click enter. This gives you a push-pin on your map.

4. Go to the push-pin spot and you will be very close. I usually recheck the distance and make it exact by hitting "goto" the beginning marked point.

Hope this helps.

I'm not so sure I would recomend this method...first off, it's not that accurate an operation to begin with even when you use the sighting marks on the case, hold the bearing, and press enter to mark the projected waypoint. Having to press "menu", scroll to measure distance, press enter and the use the panning rocker will surely have the GPS not pointed anywhere near the bearing you originally pointed at. For best accuracy, mark a waypoint where you are standing, then using the "project a waypoint" feature using the sighting marks on the GPS case.

Another point...once you use the measure distance function, the top portion of the screen is blocked and the page view locks....so if you are using "track up", the page will no longer rotate according to your path.

#7 User is offline   Sputnik 57 

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Posted 01 November 2005 - 06:35 AM

From the FAQ:

Quote

8. How do I project a waypoint? When I try, I'm stuck using miles as units. I need to project one only a few hundred feet.

When projecting a waypoint (MARK->MENU->Project Waypoint), cursor over to the little 'mi' in the lower right corner and hit ENTR. A hidden menu pops up right there and lets you change the projection units to mi, ft, yd, km, m, nm. From there, you can select miles, feet, yards, kilometers, meters or nautical miles. This thread talks more about it, and offers a screen shot (thanks jotne).

This post has been edited by Sputnik 57: 01 November 2005 - 06:35 AM


#8 User is offline   blindleader 

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Posted 01 November 2005 - 09:06 AM

Keep in mind that the same problem one has with units of distance being too coarse is present with the bearing. I'm a little flabbergasted that Garmin doesn't provide at least three digits of precision to the right of the decimal point for the degree in put. It means significant errors if you project much more than a couple hundred yards using whole degrees. Using mils is considerably more precise (about 18 times) but still is too coarse for my taste. <full rant mode> It's a calculation function not a measurement function. Calculators should work to precision beyond the capability of the measuring device. </full rant mode>

#9 User is offline   stevesisti 

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Posted 01 November 2005 - 01:01 PM

blindleader, on Nov 1 2005, 01:06 PM, said:

Keep in mind that the same problem one has with units of distance being too coarse is present with the bearing. I'm a little flabbergasted that Garmin doesn't provide at least three digits of precision to the right of the decimal point for the degree in put. It means significant errors if you project much more than a couple hundred yards using whole degrees. Using mils is considerably more precise (about 18 times) but still is too coarse for my taste. <full rant mode> It's a calculation function not a measurement function. Calculators should work to precision beyond the capability of the measuring device. </full rant mode>

If the unit is plus/minus 5 degrees, why would you want to input info in thousandths of a degree. The purpose of projecting a way point is to use the onboard compass. Given it's native accuracy of full degrees (5 at that), why would you ever want input capability to thousandths of a degree. Forgetting the garmin unit for the time being, is there even such an instrument that can measure thousandths of a degree.....heck at that accuracy, even your zipper would throw a monkey wrench into the measurement :0)

#10 User is offline   blindleader 

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Posted 01 November 2005 - 01:58 PM

Quote

The purpose of projecting a way point is to use the onboard compass.

I beg your pardonWhat?

I can use a compass, onboard or not, just fine without projecting a waypoint. The purpose of projecting a waypoint is to calculate a new waypoint. Read the rant section of my post again. Suppose I am required to project a waypoint five miles from a starting position and am given a bearing of 42.758. If I'm limited to whole degrees, the resulting waypoint is more than a hundred feet from the intended location. More than twice that if the given bearing is 42.5. Double the error again for a ten mile projection.

Actually, I know a cheat I could use to get close to the required accuracy using only whole degrees. But that's for another thread.

#11 User is offline   jacques0 

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Posted 01 November 2005 - 02:22 PM

blindleader, on Nov 1 2005, 01:58 PM, said:

Quote

The purpose of projecting a way point is to use the onboard compass.

I beg your pardonWhat?

I can use a compass, onboard or not, just fine without projecting a waypoint. The purpose of projecting a waypoint is to calculate a new waypoint. Read the rant section of my post again. Suppose I am required to project a waypoint five miles from a starting position and am given a bearing of 42.758. If I'm limited to whole degrees, the resulting waypoint is more than a hundred feet from the intended location. More than twice that if the given bearing is 42.5. Double the error again for a ten mile projection.

Actually, I know a cheat I could use to get close to the required accuracy using only whole degrees. But that's for another thread.

Pardon my ignorance (and perhaps I've led a sheltered life) but are there situations that arise where you need to project a waypoint 5 MILES away to a bearing accurate to 3 decimal places? I would hope that---at 5 miles out---the destination is a major feature that really doesn't require detailed navigation skills (i.e., a prominent butte, etc.). If that accuracy is required at 5 miles then----well---I have bigger fish to fry and better things to do.

I think that at those sorts of distances, at least for geocacheing, then just give the coords (and yes, I realize that coords are just another way of saying X miles away at Y.YYY degrees), but I think of waypoint projections as being a relatively short distance thing.

This post has been edited by jacques0: 01 November 2005 - 02:35 PM


#12 User is offline   blindleader 

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Posted 01 November 2005 - 02:55 PM

Quote

but are there situations that arise where you need to project a waypoint 5 MILES away to a bearing accurate to 3 decimal places?

What's so hard about the concept of precision in calculations? You go looking for a cache with coordinates given to a precision of .001 minutes, right? And that cache might be five miles away, right? Now suppose you are not given the coordinates, but a bearing and distance from a point...
.
.
.
.thinking?
.
.

In order to calculate the destination coordinates to .001' precision in the above case, you need to be able to calculate using bearings given with a precision better than .01

O.K. example: You're at the first waypoint of a multi-cache. The paper in the capsule says the cache is on a bearing of 42.758T at a distance of 5.033 miles. If you use 43 The point you project will be about 110 ft from the intended target.

BTW. Garmin seems to be unaware of the difference between calculation and measurement, and maybe doesn't even use a curved earth surface in it's projection calculations . I tried a projection of 60 nm on my 60C and the result was 240m from the correct answer using GRS80 earth model.

#13 User is offline   stevesisti 

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Posted 01 November 2005 - 03:03 PM

blindleader, on Nov 1 2005, 05:58 PM, said:

Quote

The purpose of projecting a way point is to use the onboard compass.

I beg your pardonWhat?

I can use a compass, onboard or not, just fine without projecting a waypoint. The purpose of projecting a waypoint is to calculate a new waypoint. Read the rant section of my post again. Suppose I am required to project a waypoint five miles from a starting position and am given a bearing of 42.758. If I'm limited to whole degrees, the resulting waypoint is more than a hundred feet from the intended location. More than twice that if the given bearing is 42.5. Double the error again for a ten mile projection.

Actually, I know a cheat I could use to get close to the required accuracy using only whole degrees. But that's for another thread.

I think you're missing the whole question...and point. The original poster asked how to project a waypoint on a 60 CS....that involves uses the on board compass, you know, the one you want 3 decimal places in. No matter what you do with the 60CS, its accuracy is plus or minus 5 degrees....period. Adding more decimal places does nothing to change that accuracy.


Use a little common sense......The "project a waypoint" function was designed to be used in cunjunction with the "sight and Go" feature. Having no decimal places is consistant with the accuracy of the compass itself and the accuracy of ones ability to sight with the case markings provided.

If you have some wierd requirement to project a waypoint to 3 decimal places over 5 mi., use one of the on-line programs to get your waaypoint and then punch in the calculated data. 99.999% of 60CS users could never dream of using 3 decimal places in practical usage.

Lastly, large style type for dramatically emphasizing your point went out of style 5 yrs ago.....unless you have an inferiority complex, std. size type is just fine for getting your point across.

#14 User is offline   blindleader 

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Posted 01 November 2005 - 08:31 PM

Quote

I think you're missing the whole question...and point. The original poster asked how to project a waypoint on a 60 CS....that involves uses the on board compass,

The OP says no such thing about a compass. Perhaps there's some virtual point, one that exists only in your own head?

Quote

you know, the one you want 3 decimal places in.

Perhaps it's time for reading comprehension training. I don't give a fig how many decimal places the onboard compass has. It's the data entry and calculation that I was discussing.

Quote

Use a little common sense......The "project a waypoint" function was designed to be used in cunjunction with the "sight and Go" feature.

"Common Sense"? If you want to cross that minefield you're welcome to it. <sarcasm=11>I don't know any Garmin engineers like you seem to<sarcasm=normal>, but I don't see anything in the manual about "sight and Go" in the section of the manual on projecting waypoints. I do see the following: "Projecting a waypoint from any map item (another waypoint, etc.) allows you to establish a new waypoint on a bearing and distance projected from that map item."

Quote

If you have some wierd requirement to project a waypoint to 3 decimal places over 5 mi., use one of the on-line programs to get your waaypoint and then punch in the calculated data. 99.999% of 60CS users could never dream of using 3 decimal places in practical usage.

Well, I'm one who does more than dream. I'm also one who doesn't have access to on line programs while in the field. Do you know the 99,999 others? Didn't think so.

Quote

Lastly, large style type

Obviously even the large type failed to get the point across to you, though it did catch your attention. So I'm somewhat at a loss how to get anything at all into your head.

Oh, wait a minute. You're not even a geocacher.

Everyone else, excuse me for wasting bandwidth on a troll.

#15 User is offline   peter 

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Posted 01 November 2005 - 08:57 PM

stevesisti, on Nov 1 2005, 03:03 PM, said:

The original poster asked how to project a waypoint on a 60 CS....that involves uses the on board compass

No, it has nothing to do with whether or not the GPS includes a compass. Most GPS receivers include the feature of "projecting a waypoint" even though they don't incorporate the magnetic compass sensor of the 60cs.

Projecting a waypoint is simply another way of specifying a location. Instead of saying the next place is at lat X, long Y, you say that it's located a certain distance and bearing (either true or magnetic) from your current location.

#16 User is offline   hogrod 

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Posted 02 November 2005 - 01:32 AM

projecting a waypoint is a really cool tool, but in most GPS i have used it is also a slightly hidden function. even the cheap lowrance ifinder go and go2 can project waypoints. the only GPS i can think of that doesn't is any of the explorist series.
on the meridain gold you had to go to the screen where it shows your current coords and hit options, it was under that menu.
on my etrex legend c, main menu, find, waypoints, pick waypoint you want to project from. once you are at the screen that lists that waypoint and its coords/name, click the option button. project waypoint is located here.
and yes if it allowed for decimal points or even half degrees you could hit the mark closer at longer distances. i tried to project over a 2mile area when creating a cache and ended up not being able to hit the mark, i was 100ft+ one way of the other. I ended up with a much shorter pojection, and even at 170meters i had to play around with the degrees/distance till i got the accuracy in close.

This post has been edited by hogrod: 02 November 2005 - 03:35 AM


#17 User is offline   fizzymagic 

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Posted 02 November 2005 - 02:55 AM

stevesisti, on Nov 1 2005, 03:03 PM, said:

I think you're missing the whole question...and point. The original poster asked how to project a waypoint on a 60 CS....that involves uses the on board compass, you know, the one you want 3 decimal places in. No matter what you do with the 60CS, its accuracy is plus or minus 5 degrees....period.

The OP poster said nothing about internal compasses. And waypoint projection doesn't depend on magnetic compasses anyway.

Just because the internal compass in the 60CS sucks doesn't mean that it can't project waypoints accurately.

A waypoint projection involves projecting a geodesic a specified distance in a specified direction. Accurate projections are usually done using azimuths from true north, not magnetic north. Surveyors do projections accurate to less than an inch over distances of several miles.

Claiming that it's useless to do accurate projections because the internal compass of the GPS is inaccurate is more or less equivalent to saying that quarters and nickels are the same size because your ruler is so bad. It just doesn't make any sense.

#18 User is offline   stevesisti 

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Posted 02 November 2005 - 04:33 AM

fizzymagic, on Nov 2 2005, 06:55 AM, said:

stevesisti, on Nov 1 2005, 03:03 PM, said:

I think you're missing the whole question...and point.  The original poster asked how to project a waypoint on a 60 CS....that involves uses the on board compass, you know, the one you want 3 decimal places in.  No matter what you do with the 60CS, its accuracy is plus or minus 5 degrees....period.

The OP poster said nothing about internal compasses. And waypoint projection doesn't depend on magnetic compasses anyway.

Just because the internal compass in the 60CS sucks doesn't mean that it can't project waypoints accurately.

A waypoint projection involves projecting a geodesic a specified distance in a specified direction. Accurate projections are usually done using azimuths from true north, not magnetic north. Surveyors do projections accurate to less than an inch over distances of several miles.

Claiming that it's useless to do accurate projections because the internal compass of the GPS is inaccurate is more or less equivalent to saying that quarters and nickels are the same size because your ruler is so bad. It just doesn't make any sense.

I don't think the internal compass on the 60 CS sucks.....for what it's supposed to do I think it works just fine. My point was that it's useless to use the compass projection to degrees three decimal places considering the compass accuracy. And the way the unit is set-up, it's obvious Garmin chose the accuracy units they did because they intended the primary use to be with the "sight and go" function of the unit.

In fact for general navigation, the unit with it's native resolution and accuracies is just fine.

Where would you need three decimal place precision.....well in the example given it's a heading to a cache........With most handheld units out there not being able to project to three decimal places, why do you think the cache creator used three decimal places? He used three decimal places to make the cache more challenging, knowing that to find the cache you have to put in a little more effort and go through a second step. He didn't expect you to cry and complain about not having three decimal places in your handheld....he expected you to be resourceful and find an alternative way of arriving at the cache without just entering the info into your GPS.

And if it wasn't the projection degrees, the hider would once again find something else to add to the degree of challenge, forcing you to use sources which are not just available in your handheld. That's supposed to be the fun of it.

#19 User is offline   Team Perrito Blanco 

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  Posted 02 November 2005 - 05:35 AM

I'm disappointed that these units can't do a simple projection accepting input in decimal degrees. The unit knows where you're standing, it SHOULD know the COORDINATES of the north pole, the rest is simple math. It shouldn't even need to use the compass.

#20 User is offline   EScout 

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Posted 02 November 2005 - 12:17 PM

When projecting, you get more precision using mils instead of degrees, so if your GPS lets you, use mils. Most of the Garmins have mils and whole degrees. The Meridian GPSrs let you project in 2 decimal places (hundredths of a degree) which works very well. The eXplorists do not project at all. In the field, the "Navigate v2.2" program on your PalmOS works very well. Do your precision projection using this, and then imput the projected coords and do a "GOTO" using your GPSr.

#21 User is offline   Tommmmm 

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Posted 19 February 2011 - 02:16 PM

Method 1. Walking AWAY from the know location to the required distance with a bearing 180 degrees the opposite direction.

for example. Set you GPSr for "The 1st Geo-Keteer *Athos*" but walk away from it .14 miles bearing 117degrees. (297-180=117)

The bearing number is usually defaulted on your arrow screen but you may have to make changes.


Method 2 Project a waypoint using your etrex Legend GPSr,.

I think ALL 'etrex GPSr' models have this feature built in.

For example

a. Call up "The 1st Geo-Keteer *Athos*" (The location you want to do a projection from)(DO NOT hit the "map" or "go to" buttons.)

b. Next, press the menu button on the left side.

c. scroll to "Project Waypoint"

d. enter the "degrees and distance" 297 degrees and .14 miles

e. tab over to "go to"

f. start walking.


Method 3

Use the GSAK program.

Right click on the cache you want to do a projection from.

Choose "project waypoint" from the choices

enter the distance and the bearing data and hit enter.

It will give you the exact coordinates.



Method 4

If there is more than one location you can project from to get to the same goal location, like in the Geo-Keteer Series, you can eyeball it just using just compass. However the final's general location will need to be visible from each site.

From the 1st location using the bearing and distance pick a landmark.
do the same from the second location.

Where those two routes intersect is the location of the cache.

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