I use GPS to establish elevations a lot...mainly to tie into the existing town topography & GIS. So the exact elevation isn't always critical.
But if it is, I always check onto a known benchmark (or two)...almost every time it hits within a tenth....then re-check a few hours later with different geometry...same thing..
When GPS is used right it really is an amazing tool...
Yep, I've been using GPS with a regional VRS for almost 5 years and I'm still amazed at the results I get, every time I use it......
...almost every time it hits within a tenth....then re-check a few hours later with different geometry...same thing..
>
> When GPS is used right it really is an amazing tool...
A tenth? A tenth?;-)
We have Control Networks run in three cities and a common county in my area. There are 2 cities just west of us that have great networks run through them with what I would consider very stable and repeatable control. We have worked on the Grid and developed small scale ground projections with them.
Nearly every time I go out on either of these two control networks, I can check into any other point within 0.03' H & V. Not quite, but nearly every time.
Oh and the control in those two cities, Nampa and Caldwell, Idaho...were done by none other than this forum's very own Shelby Griggs.
Yeah Rob, we really don't have anything that nice here...send Shelby out our way please!!
and when GPS is NOT used correctly it can create a mess!!