Something about GPS

[bfdiesel]

The SAR team I am part of recently had call where the lost person was able to send his/her "GPS coordinates". Long story short the first coordinates were a mile and a half off. The person texted a second set of coordinates that were 44 miles off. The ping of the cell phone gave us a third set of coordinates that was within a half mile from there the rescue was made.

Morale of the story have an actual GPS and know how to use it. Don't trust cell phones to save you as they may tell you the wrong thing and don't get lost in a white out blizzard.

 

[UK4X4]

There are many - geospacial co-ordinate systems

All have a diferent system in relation to maps- maps have a whole other orientation system

the sender did nothing wrong as such- he probably used the system he understood and used.

The reciever was happy using his prefered system and the coordinates worked- although wrong

having done GPS based offroad events on 3 continents I have had similar issues

each coordinate system has its own reference point/system- You need to insure that both parties are using the same system !

This explains a little


http://www.squidoo.com/GPS-coordinate-systems-datums

 

[bfdiesel]

That is all understood. I am just advising caution if someone is going to buy and use a cell phone as their gps. Especially agps make sure it has gotten past using the cell towers and is actually looking at the satillites, or it may be off up to 44 miles that I have seen proven.

 

[Doctor W]

A similar thing has happened here in Australia where state SAR and the lost party were in contact by cell phone with a rescue party and could from the top of their rugged bush top mountain could see and correctly describe a particular town on another mountain about 5 (very) rugged miles east from them......however their cell phone's "independant" GPS system was telling them they were about 140 miles to the west on the banks of a large river!........

......... I guess I wouldn't trust the GPS accuracy and capabilities of a device that also has an app for a healthy scheduled diet times for your pet kitty cat!!!!

 

[Driver-Navigator]

This has happened before and some SAR & other agencies reportedly have a policy against using such coordinates, which is a shame. I guess they get cranky when someone is in an entirely different *county* and is not capable of relaying that information. I agree that the lesson is to know how to use your GPS & be educated in such things. Just reading off numbers with no clue as to coordinate systems, datums, etc. is just a case of ignorance.

In my experience, nearly all new users of outdoor/handheld GPS also rely on a compass feature that they don't understand either, and suffer accordingly. Again, some education is the cure.