Re: Surveying in the UK

Paul
The vast majority of sites are just put on a local grid system (for E & N),
although most are related back to the OS level datum (Newlyn).
Due to the easy availability of OS digital data many clients are now asking
for surveys to be related to the OS grid, although what they really want (at
least this is what I try & tell them they really want!) is to fit the survey
into the surrounding OS digital mapping. Two entirely different things. Some
of the OS digital mapping if so far out (we recently had some that had a
road 10m out of position) that using GPS to tie back to the OS grid will
often give you no better a fit that just overlaying your survey with the OS
in CAD. I'm only speaking of quite small surveys for small projects (the
vast majority of jobs for most of us), bigger site may well need linking
properly to the OS grid.
Also site control often differs from the control of the original survey. The
surveyor will usually have his grid orientated to the north (a rough compass
bearing very often), but the architect or engineer will usually have the
site grid running along a building axis or some other major feature that is
to be constructed on the site. Just to add to the confusion!
Hope this is on some help.
Kind regards
Steve Bury

Bury Associates Limited
www.buryassociates.co.uk
T. 01905 26222
F. 01905 22555
"Paul" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> I did register and look at the information on www.gps.gov.uk. If one
> was undertaking  surveys using GPS this site is great. But are most
> surveys in the UK undertaken or on site control established with GPS.
> I appreciate the benefits that GPS has however the cost for small
> firms has always tended to be costly. If GPS the only way to tie to a
> survey datum in the UK I will have to brush up on my use of it.