Hi Don,

It's not really in error - just one of the many issues relating to map projections and reference systems on a near sphere.

As long as you know how the different systems relate, you can switch between them.

I used a map based on a different reference system during the summer - to convert between the GPS and the map reference grid you had to add 127m E and 26 N.

Dave L

Here's the handheld GPS reading for the SE corner taken by unknown on the net plotted on GE.

There's only a few metres difference, depending on where he was standing at the time.

The SE corner reading is more reliable, as most satellites are towards the equator, ie S of the GP.





Edited 1 time(s). Last edit at 11/15/2006 08:02AM by Dave L.