Direction Needle Gone Nuts.

[+aintnorock]

Hi-

 

We just spent our first weekend geocaching with a Garmin etreex Legend. I really like all the information it gives you, but I found that if you parallel a waypoint (e.g. say a waypoint is on 4th street midway through the block, and you're driving on 3rd street), and then drive PAST the waypoint which was 90 degrees hard right or left, the directional needle on the Legend just goes beserk and points in all different directions, usually 180 degrees the wrong way. I solved the problem by finding the waypoint again and resetting the GPSr.

 

Is this a common problem? What causes it? How do you resolve it?

 

Thanks,

carl

[+Chaos A.D./aka Arlsdaddy]

Hi-

 

We just spent our first weekend geocaching with a Garmin etreex Legend. I really like all the information it gives you, but I found that if you parallel a waypoint (e.g. say a waypoint is on 4th street midway through the block, and you're driving on 3rd street), and then drive PAST the waypoint which was 90 degrees hard right or left, the directional needle on the Legend just goes beserk and points in all different directions, usually 180 degrees the wrong way. I solved the problem by finding the waypoint again and resetting the GPSr.

 

Is this a common problem? What causes it? How do you resolve it?

 

Thanks,

carl

Something many people forget is the compass needs to be calibrated EVERYTIME you replace the batteries. Hope that's all it is.....

[+BlueDeuce]

Something many people forget is the compass needs to be calibrated EVERYTIME you replace the batteries. Hope that's all it is.....

 

That's the first thing that always pops into my head, but the Legend doesn't have a compass.

[+Chaos A.D./aka Arlsdaddy]

Something many people forget is the compass needs to be calibrated EVERYTIME you replace the batteries. Hope that's all it is.....

 

That's the first thing that always pops into my head, but the Legend doesn't have a compass.

My bad for refering the bearing pointer as being a compass...if it has an arrow and points, it's a compass to me Still, doesn't it need calibrated also, so it knows which way is which? Wife has the legend, but I haven't played with it much. I know I had to calibrate my old Sportrak Color though.

[+aintnorock]

Something many people forget is the compass needs to be calibrated EVERYTIME you replace the batteries. Hope that's all it is.....

 

That's the first thing that always pops into my head, but the Legend doesn't have a compass.

My bad for refering the bearing pointer as being a compass...if it has an arrow and points, it's a compass to me Still, doesn't it need calibrated also, so it knows which way is which? Wife has the legend, but I haven't played with it much. I know I had to calibrate my old Sportrak Color though.

 

Let me try to explain the issue more clearly.

 

The setup allows you to choose whether North is at the top of the navigational page, or whether it should be pointing to the direction you're travelling. I've chosen the second option.

 

Say I'm 5 miles away from the waypoint. The waypoint is actually on 4th street, I'm on 3rd street. 4th street is parallel to 3rd street on my right. After I start travelling towards the waypoint, the directional arrow will be pointing almost straight ahead on my Legend - it will be pointed a few degrees right of dead center. The closer I get, the needle will start being more and more degrees to the right until I get to the block of the waypoint. When I am closest to the waypoint, the needle would be pointing 90 degrees to the right, but AFTER I PASS that point, the needle sometimes points the wrong way, and the further away I go, the more wrong it gets until it is sometimes 180 degrees in the wrong direction. The only way I can tell that I've passed the waypoint is by looking at the distance from the waypoint, and it goes up.

 

I can resolve the issue by resetting my "goto" waypoint, and it seems to be able to "find" it again.

 

Hope this makes sense.

 

carl

[zapped]

When I am closest to the waypoint, the needle would be pointing 90 degrees to the right, but AFTER I PASS that point, the needle sometimes points the wrong way, and the further away I go, the more wrong it gets until it is sometimes 180 degrees in the wrong direction. The only way I can tell that I've passed the waypoint is by looking at the distance from the waypoint, and it goes up.

 

I can resolve the issue by resetting my "goto" waypoint, and it seems to be able to "find" it again.

 

I might be guessing incorrectly, but it sounds to me like your pointer is set up as a "course pointer" instead of a "bearing pointer". Almost as if the GPS knows you passed your waypoint and now it's pointing straight ahead (instead of at the waypoint behind you) because it's trying to follow the roads to get you back to the urban waypoint. In other words, perhaps it's telling you to stay on the road heading away from a waypoint for a bit, then it will maybe tell you to make a couple of right turns to get back to it?

 

Try bringing up the menu when you're on the compass page & toggling between course pointer & bearing pointer. Apologies if I'm not getting the exact semantics right.

 

EDIT: another simpler possiblity if you're in an urban environment (3rd st / 4th st) is that buildings around you are blocking satellites, increasing the circle of uncertainty, and causing the pointer to oscillate around.

Edited June 1, 2006 by zapped

[+aintnorock]

 

I might be guessing incorrectly, but it sounds to me like your pointer is set up as a "course pointer" instead of a "bearing pointer". Almost as if the GPS knows you passed your waypoint and now it's pointing straight ahead (instead of at the waypoint behind you) because it's trying to follow the roads to get you back to the urban waypoint. In other words, perhaps it's telling you to stay on the road heading away from a waypoint for a bit, then it will maybe tell you to make a couple of right turns to get back to it?

 

Try bringing up the menu when you're on the compass page & toggling between course pointer & bearing pointer. Apologies if I'm not getting the exact semantics right.

 

You are absolutely correct - it was set on Course Pointer. Thanks for the tip! Your explanation makes perfect sense.

 

carl

[+apersson850]

No, it does not, if it's an eTrex Legend, since the Legend can't navigate along roads. It knows about straight course lines only.

The Legend C can compute the route along the roads, but that's something else.

 

Still, the course pointer would not start to turn to the right, as you approach the waypoint. It will always point in the original direction to the waypoint, parallel to the course you should have taken to begin with.

 

If we still assume it's a Legend, not a Legend C.

[Neo_Geo]

Still, doesn't it need calibrated also, so it knows which way is which?

The Legend's compass is not a magnetic compass. It shows direction based on your movement as derived from calculations of the GPS data it receives from the satellites. The compass is constantly "calibrated" automatically by virtue of the GPS data it receives.

[zapped]

No, it does not, if it's an eTrex Legend, since the Legend can't navigate along roads. It knows about straight course lines only.

The Legend C can compute the route along the roads, but that's something else.

 

I eBay'd my original Legend (B&W) in favor of a new Legend Cx, but when I had Metroguide USA v3 map sections downloaded to my original Legend, I'm pretty sure it navigated along roads! I used it for navigation that way on vacations for a couple of years, but maybe I was hallucinating. Dunno, it's been a long day...

[+aintnorock]

No, it does not, if it's an eTrex Legend, since the Legend can't navigate along roads. It knows about straight course lines only.

 

Still, the course pointer would not start to turn to the right, as you approach the waypoint. It will always point in the original direction to the waypoint, parallel to the course you should have taken to begin with.

 

 

It is a legend, not a legend/c

 

Why does the arrow continue to point in the original direction? Does anyone know?