Community Forums

Midniteoyl · 10-11-2012, 10:20 PM

"passenger side airbag"

Dogpatch · 10-11-2012, 10:29 PM

Nice way of putting it Jim!

Possum · 10-11-2012, 10:43 PM

Way last spring we left Silver Creek New York and were headed to Rome NY for the night. I set our GPS to the address of the campsite and set "Avoid Toll Roads" on. The frigging thing took us on a huge loop into the south east and we ended up staying at Babcock Hollow Campground in Bath, NY. We were closer to Rome that morning when we left Silver Creek.

Shutterbug71 · 10-13-2012, 01:11 PM

My mom told me that the other day she drove my brother to a Dr.'s appointment and they used his GPS to find the office. Well it took her to the end of a street, and then gave this instruction:

"Proceed forward 30 feet to your destination"

She looked ahead and there, on the other side of a fence and a 100 foot drop, was the parking lot she was trying to get to!!

Amy

MRBB · 10-13-2012, 02:07 PM

I love the commerical where a car is going off the cliff and you hear the GPS saying "Recalculating, Recalculating....

desertranger · 10-13-2012, 04:39 PM

I've spent my life reading maps, navigation. Even took several USCG courses in navigation and was certified as a navigator in the AF. Even taught orienteering and introduced people to Geocaching.

Got my first GPS in 1984. It weighed 7lbs and only displayed numbers. Today I have a Delorme PN20 mapping GPS that weighs 250grams for flying driving and hiking, driving but not nautical. Load map sectionsto an SD card, phot imagery and more.

All of the stories you've heard about GPS leading people astray are true. The couple lost in the snow in Oregon and the boy who died because his mother took a wrong turn into Death Valley faithfully following the GPS.

A couple of years ago I got caught in one of these GPS adventures. Entering the Sieraa Nevada mountains at the south of Lake Tahoe it was supposed to bring me out near Minden, NV. Following a detour the GPS recalculated and took me back to Tahoe. After several resets and creating new routes the GPS finally brought me out of the Sierra Nevada Mtns in Monitor Pass, Ca. 80 miles south of where I wanted to be, Minden NV several hours later.

This prompted me to do some research and write a magazine article about it. So here are a few little known facts about GPS, especially those used for road navigation.

GPS does not calculate time renaming or ETA from your actual speed. They use the posted speed limits on the road. To get that answer your GPS has to have a feature called VMG or velocity made good.

When you search for a place to go i.e. Trader Joes, the GPS gives you the straight line distance, not the route distance.

Some cell phone GPSs require the presence of a cell phone network to give tell you where you are. Buy a cell phone that has stand alone GPS.

To test the ability of a GPS to give accurate data I used 3 GPSs. A Magellan SportTrak, Delorme PN-20 and a Garmin Nuvi 50 to track the trip from Quartzite AZ to Palm Springs, CA. 90 Miles. Driving at 75mph it shold have taken me just under an hour and 15 mins. The The Magellan and Delorme both said over 90 mins. The Delorme gave an ETA of 1:45 that's over the time to drive the distance at the speed limit. Only the Garmin gave me an accurate arrival time and it was off by 5 mins. The Delorme was off by 20 mins until I was less than 20 mins out. BTW When I switched the Magellan and the Delorme to hiking mode the time to cover the distance on foot was calculated at over a week and a half. The actual tie to hike from Quartzite to Palm Springs is actually a tad over 3 1/2 days.

Draw your own conclusions but from now on I carry a map and compass in addition to my GPS.

bdickson · 10-13-2012, 04:43 PM

We view our GPS like President Reagan viewed the Soviet Union: "Trust, but Verify".

Midniteoyl · 10-13-2012, 05:24 PM

Quote:

Originally Posted by desertranger

I've spent my life reading maps, navigation. Even took several USCG courses in navigation and was certified as a navigator in the AF. Even taught orienteering and introduced people to Geocaching.

Got my first GPS in 1984. It weighed 7lbs and only displayed numbers. Today I have a Delorme PN20 mapping GPS that weighs 250grams for flying driving and hiking, driving but not nautical. Load map sectionsto an SD card, phot imagery and more.

All of the stories you've heard about GPS leading people astray are true. The couple lost in the snow in Oregon and the boy who died because his mother took a wrong turn into Death Valley faithfully following the GPS.

A couple of years ago I got caught in one of these GPS adventures. Entering the Sieraa Nevada mountains at the south of Lake Tahoe it was supposed to bring me out near Minden, NV. Following a detour the GPS recalculated and took me back to Tahoe. After several resets and creating new routes the GPS finally brought me out of the Sierra Nevada Mtns in Monitor Pass, Ca. 80 miles south of where I wanted to be, Minden NV several hours later.

This prompted me to do some research and write a magazine article about it. So here are a few little known facts about GPS, especially those used for road navigation.

GPS does not calculate time renaming or ETA from your actual speed. They use the posted speed limits on the road. To get that answer your GPS has to have a feature called VMG or velocity made good.

When you search for a place to go i.e. Trader Joes, the GPS gives you the straight line distance, not the route distance.

Some cell phone GPSs require the presence of a cell phone network to give tell you where you are. Buy a cell phone that has stand alone GPS.

To test the ability of a GPS to give accurate data I used 3 GPSs. A Magellan SportTrak, Delorme PN-20 and a Garmin Nuvi 50 to track the trip from Quartzite AZ to Palm Springs, CA. 90 Miles. Driving at 75mph it shold have taken me just under an hour and 15 mins. The The Magellan and Delorme both said over 90 mins. The Delorme gave an ETA of 1:45 that's over the time to drive the distance at the speed limit. Only the Garmin gave me an accurate arrival time and it was off by 5 mins. The Delorme was off by 20 mins until I was less than 20 mins out. BTW When I switched the Magellan and the Delorme to hiking mode the time to cover the distance on foot was calculated at over a week and a half. The actual tie to hike from Quartzite to Palm Springs is actually a tad over 3 1/2 days.

Draw your own conclusions but from now on I carry a map and compass in addition to my GPS.

Incorrect - the ETA IS based on your speed. The initial ETA is based on the speed limits known AND your history following them. If you normally go 5 over, the GPS will take that into account. If you speed up or slow down, the ETA WILL change accordingly. Traffic is also taken into account. On TomToms, the traffic history is also taken into account. This comes from historical data of other TomToms.

The route calculated is NOT straight line, but based on the internal maps and follows the legal road. Sometimes the maps are mis-marked and errors occur.