Ifish poker run ... gps navigation exercise

[Pilar]

For all of you salty dogs ... a little orienteering and an excuse to play with a gps on the water

http://www.ifish.net/ubb/ultimatebb....c;f=1;t=023552

[id. painter]

Sound like a good time. I have spent the last 7 months looking at my boat in the garage.
Im so hard up for a fishing trip. Ill be over in your neck of the woods next week , but plan to keep my line wet the whole time. I would love to play though. id. p.

[Beer Waggin]

From Pilar (the other post)

Why .. because I have personally observed some navigationally challenged behavior and would like to give everyone a chance to practice. Besides you didn't think all the Tunaholics meetings would be in restaurants or bars did you?

<font size="2" face="verdana,arial,helv">Brings up an interesting point that I learned about GPS's on the last trip. Just because you have two of them, doesn't mean they'll both take you to the same point, hence the lesson.
On the trip out two weeks ago, we dropped the crab pots, I marked the spot on my hand held GPS and wrote the numbers down for safe keeping and my records. When we returned, we went to the same numbers via a different GPS and no crab pots were to be found. I turned my hand held back on and discovered the two GPS's were at different spots on the map. They were far enough apart to put us on the beach instead of through the jaws on a foggy day, lucky for us it was clear and sunny.
Brings up one heck of a saftey issue, not only should you have a second GPS for a back up, but the numbers showing should match as well.
I'm not sure if this was a battery issue or a GPS issue. When I replaced the batteries in mine and went looking for the pots, it took us straight to them. Makes you wonder.....

[ 04-08-2003, 01:37 PM: Message edited by: NorRivDave ]

[Pilar]

NorRivDave, I did not mean to pick on you guys ....

I have had that same thing happen to me, twice now. Both times it was a transposed number

IE: N45 22.994' W122 38.757' becomes
....N45 22.994' W123 38.757'

Or something like that. 1 degree of lattitude or longitude is many miles off. Now I type it in and check it three times. It is very easy to mistype and even easier to look at the typo and miss it. A new route gets tested in unlimited visibility, daylight conditions before I trust it in a pinch.

Practice makes perfect

[Beer Waggin]

Ahh, a little nudge in the side never hurt anybody. I take it in stride.
It was a good lesson to learn on a great day, but it still baffled the both of us.

[Chum King]

NorRivDave,
In most cases your GPS unit should take you to the same "spot". However, you should double check and make sure that the datum that you are using is the same on both units. If you are using two different datum on the two GPS units then entering a GoTo location from one unit into the other will end up taking you to a slightly different location. You should check your owner's manual on how to set the datum used. I believe that a good datum to work from in this area is WGS84.

[corrirod]

ChumKing has a good point but I think the standard is WGS84. I would look at how both of the GPSs' Lat/Lon format was setup. It sounds like you each had your GPS set to a different format. For instance, a format of:

dd* mm.mmm

while his was set for:

dd* mm.mm

So when your GPS reads 125 45.450, he types in 125 45.45, or vice versa, and you get two different coordinates.

Check it out and let us all know if you figure it out.

[ 04-08-2003, 11:46 PM: Message edited by: corrirod ]

[Beer Waggin]

My fear is that if I reset my GPS, I will never find my spots again.
I have two backups, so one of those will be reset, corrected if need be and verified by my third and then compared to the one I use. I may have to carry around multiple GPS's for a while to get correct numbers.
This could all be Edsr's problem and not mine too. You following all this Ed?

[Miss B Haven]

NorRivDave - Enquiring fishbrains just have to know..... were there any black helicopters flying around when this GPS thing happened? :shocked:

[Beer Waggin]

I'm not following you...
Did I miss a joke somewhere?

[Miss B Haven]

Oh no Dave -it's no joke! [img]graemlins/1zhelp.gif[/img] I've seen them. Put "black helicopters" in the search feature on the main page and you'll get a sampling of the fear and respect we have for them! :grin:

[Fishplay]

John,
I think I'm going to be too busy to play. It sounds like fun though. I have removed my sled from the market and I'm going to be busy with rigging for a bit. Suspension seats, trim tabs, fuel cell, kicker bracket, relocate box mounted seats, new sonar/GPS unit, Tr-1 autopilot.

I'm even considering replacing the pump with an outdrive unit if I can find one at the right price.

It's not the SeaSport or Osprey I wanted but it will work for another season or two.

Have fun at the Poker Run!

[corrirod]

Dave, the more I think about it the more I believe what I said in the earlier post is true. I really believe that was the problem. There is no way a gps should be off with another gps by any substantial distance. All things being equal, meaning the gps' are setup the same with lat/lon format, reading intervals, etc., the diffence between the 2 should be less than 30 ft. Obviously the more satellites tracked by a gps, the more accurate it is but even with only 3 satellites a gps should be accurate to within 30 ft.