Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Bench Marks

Bench Marks

Bench Marks

I have been asked to provide a method of providing a bench mark AOD on a site, that is about 2 miles from anything that could be used as a level datum and the site is surrounded by undulating terrain and thick woods!  Is there an easy way of setting up this bench mark without using a dumpy level / total station to transfer the level over the 2 miles?

RE: Bench Marks

How accurate does the benchmark need to be?  

Can you use a differential GPS?  With post processing, we've gotten good results for our applications, but we only need to be accurate to about 1 cm


Eng-Tips Policies FAQ731-376

RE: Bench Marks


10mm should be accurate enough! although i have very little experence with differential gps and post processing, is the kit easy to use? is the kit easy to hire? would the time saved ofset the hire cost, compared doing it the traditional way with a dumpy level?



RE: Bench Marks

Well, most surveyors that you could hire have DGPS rigs, and they'd do the same postprocessing.  

The cost of the hardware is pretty steep, I think we paid something like $10K for the Trimble DGPS and the software for acquiring the correction factors and doing the post processing.  

I would think that hiring the surveyor would be the most economical route, particularly if this is a one-time event.

We purchased our hardware because we expected to be doing this sort of thing relatively often and felt that owning the hardware gave us some additional flexibility.  


Eng-Tips Policies FAQ731-376

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close