Expect larger Errors.

[Wise Old Owl]

It appears all over the place while I was playing with several GPS systems. The border stones of the Mason Dixon line over the years have been replaced and don't expect accuracies of 16 foot when the maps and Google Earth are off by 275 feet! I discovered the error while looking for the cave in Delaware some supposed 60 feet from the border. So don't expect some lines on the maps to line up exactly.

[Tin Man]

I followed the GPS in my truck today... drove right up someone's drive and across a faint lane to the adjoining road.

[beakerman]

That's ok a few years ago when I was in Louisiana I was driving across teh river on 310. I know I was on a bridge because I could breathe but according to all the GPS mapping software I was driving on water...the bridge was almost half a mile up river from me...now that is not a trivial error. I've seen it since then with other locations taht are easy to pinpoint on the map like intersections and such too.

[Old Grouse]

So, ah, what you're all saying is that you still have to use your wits despite the promise of electronic perfection?

[Great White]

I have observed similar issues as well. The problem is the data may not have been originally gathered by GPS. In fact, digitized maps are the usual source. Errors always appear. The lines look great on a the original 1:25000 or 1:50000 map but when you go into the real world they are off by a few hundred meters. Don't forget about GPS errors as well.

Maps, either paper or digital, are only an abstraction of the real world. They will never have a scale of 1:1.

I remember my father once examined a USGS topo map and found a large river that was missing in one map edition but later reappeared in a newer edition.

[Tin Man]

So, ah, what you're all saying is that you still have to use your wits despite the promise of electronic perfection?

some need a little more help...

http://blindhiker.com/

[beakerman]

So, ah, what you're all saying is that you still have to use your wits despite the promise of electronic perfection?

Yed unfortunately folks are relying on the accuracy of the technology rather than acutally taking a look at what is happening.

This is something I have been noticing for some time and it came to a head with me just 2 weeks ago when I was doing th orienteering event at our district camporee....i had Eagle scouts that could not orient a topographic map nor could they take a simple bearing on the map or inthe real world.

[Tin Man]

Yed unfortunately folks are relying on the accuracy of the technology rather than acutally taking a look at what is happening.

This is something I have been noticing for some time and it came to a head with me just 2 weeks ago when I was doing th orienteering event at our district camporee....i had Eagle scouts that could not orient a topographic map nor could they take a simple bearing on the map or inthe real world.

I helped our troop run an orienteering event at the Klondike this year. Hopefully, a few learned how to use a map and compass and will do better at the Fall Camporee where we will be doing this again. Many want to teach gps and I argue there really is nothing to teach except how to check with a map and compass which rarely need a change of batteries.

[beakerman]

I helped our troop run an orienteering event at the Klondike this year. Hopefully, a few learned how to use a map and compass and will do better at the Fall Camporee where we will be doing this again. Many want to teach gps and I argue there really is nothing to teach except how to check with a map and compass which rarely need a change of batteries.

Yeah I was really embarrassed for the Eagles but I had leaders that failed too. Maybe I was too hard on them but I learned this stuff when I was 10-11 years old why can't they?

I'm refocusing our troops orienteering on topographic maps...I found that my predecessor just used road maps. So much for even attempting to take into account elevation changes...

[Wise Old Owl]

Well don't be too hard on them.... Those Eagles need practice, practice...

Hey pit the Adults vs the Eagles!

[Wise Old Owl]

Anybody else see big errors on this equipment?

[ki0eh]

I've seen topo maps stored in the Garmin GPS be off by 100 meters or have really old road base info, like 30 years out of date. No map is perfect. Any map, like any other human created communication, needs to be used critically. Just like postings on an Internet forum.

[hellomolly]

http://maps.google.com/maps?hl=en&q=new+york&um=1&ie=UTF-8&hq=&hnear=New+York,+NY&gl=us&ei=S7LZS6yPM4KC8gbB wPhG&sa=X&oi=geocode_result&ct=image&resnum=1&ved= 0CBIQ8gEwAA

My favorite: Direction #46: Kayak across the Pacific Ocean, 3,879 miles.

[garlic08]

A lot of areas, especially out West, were surveyed "from the bar".

There's also a real basic problem with projecting a round surface onto flat square paper. There has to be an error somewhere.

Coordinate systems have changed over the years, too. Look in the GPS menu--NAD27 or WGS84? You need to pick the right one for your map. That has caused some issues for me before.

[Two Speed]

A lot of areas, especially out West, were surveyed "from the bar".

Out west wasn't the only place that occurred. The Pine Barrens scandal in Georgia is one I'm aware of.

There's also a real basic problem with projecting a round surface onto flat square paper. There has to be an error somewhere.

Gonna second that.

Coordinate systems have changed over the years, too. Look in the GPS menu--NAD27 or WGS84? You need to pick the right one for your map. That has caused some issues for me before.

Even better, the current geoid is constantly being updated, so there will always be some "wiggle" in the data.

Really, the question is will the equipment you're using, be it map & compass, GPS, Ouija board, whatever, get you close enough to your destination that you can work it out?

[Connie]

I was at Champoeg State Park, Oregon, for a day, and saw Scouts doing an orienteering course. After the event, I met the lady orienteering instructor, from a reasonably local orienteering organization, that was asked to help lay out the course for the event.

I wish I remember the name. I do have the brochure, somewhere around here.

I mentioned this, because orienteering groups put on events and these people would be a good resource for helping get instruction to the scouts and other groups. Maybe attend one of their events, after a little "orientation" of course.

I couldn't resist!

[myotheralt]

I helped our troop run an orienteering event at the Klondike this year. Hopefully, a few learned how to use a map and compass and will do better at the Fall Camporee where we will be doing this again. Many want to teach gps and I argue there really is nothing to teach except how to check with a map and compass which rarely need a change of batteries.

I had the batteries die on a map once. It was horrible, I couldn't unfold it or anything!

[Wise Old Owl]

Uhh yea but my map doesn't burn,,,,

[Buzz_Lightfoot]

http://maps.google.com/maps?hl=en&q=new+york&um=1&ie=UTF-8&hq=&hnear=New+York,+NY&gl=us&ei=S7LZS6yPM4KC8gbB wPhG&sa=X&oi=geocode_result&ct=image&resnum=1&ved= 0CBIQ8gEwAA

My favorite: Direction #46: Kayak across the Pacific Ocean, 3,879 miles.

Heheh.....Untitled.jpg

Darn, came out too small. Google driving directions from Tokyo to New York.

[lilricky]

Just a question, when you guys experience these errors with your GPS's, how many satellites are connected to you? You do know that depending on the time of day, obstacles like buildings,trees, mountains,etc, and weather conditions, the accuracy of your device can be anywhere from 10 feet to over a mile. Just something to think about. GPS devices are not 100% accurate at all times, nor are they designed to be.