Handheld GPS - OS Grid Refs
Q. hi, I,m thinking of exploring wilder parts of britain, and although I'm happy enough with a map and compass, I'm considering getting a garmin etrex 10 as a back up. I have seen from this site, that the etrex 10 provides a os grid ref if you program the handheld. this may sound a silly question but do you also need to input the scale of the os map (ie 1;25,000 or 1;50,000) or would the grid ref calculated by the garmin refer to both scales???? If I sound dumb, I apologise in advance. cheers tom, lincoln
Tom O'Boyle, Lincoln
A. No, you do not need to input the map scale.
A 12 figure GPS Waypoint (e.g. NY 21538 07204) donotes a particular point on the earth's surface and is accurate to 1 metre (NY 21538 07204 is the GPS Waypoint for the summit of Scafell Pike). This is the same whatever the map scale is. NB. While the GPS Waypoint is accurate to 1 metre, GPS Devices themselves can only be relied upon to be accurate to about 25m.
For more questions and answers about GPS Waypoints see Walking & Hiking Questions & Answers about GPS Devices and GPS Waypoints
Hope this helps . . .