Topo layout

"Architect" is the first problem. This is not uncommon for a request to be made with a 50' grid. Seems this is the norm for several. Proceed with providing a "Topographic Survey". One they can design from and depicts the site characteristics. Many Architects do not understand the concept that the 50' grid may not fit the bill for providing. Call them and explain. Generally speaking most of the specs are based on a boiler plate contract that seems to fit some, but not all sites.

If they don't seem to grasp the idea then interpolate prior to releasing the final product.

I usually set a coord pt in the cad dwg at the grid intersections, then the gun will tell me where to get the shots.

Mr. Adams:

All I have is a manual total station.

I did a topo of several acres recently 15-20 degree slope for 400', pretty darn even. 12-15 shots along the top, 15-15 midway and 12-15 along the bottom. That was it. Did not miss a thing that the hallowed 50' grid would have picked up.
Tops and toes, high spots and low spots. Drop your 50' grid in afterwards and let the software put the elevations in. Later visits for staking revealed no problems at all. If they want see an elevation on a 50' grid, I got it. If they want to pay for shots every 50', that's another matter!

I agree with the advice to try and talk the architect out of a strict grid. However, if he insists and you don't want to stake the grid intersections, you can always shoot the topo and make sure it's accurate enough for you to interpolate the grid elevations, showing them on your survey.

Old....maybe I should have asked about the site. Is it flat? Perhaps a 50' would fit the bill. Generally speaking to layout a 50' (especially flat) compared to your pacing 50' shots would not make a hill of beans if you had to create contours.

JB has it with what he said. Just run break lines and get the necessary shots to fill in the holes. When you said you only have a manual station....what does that mean? Do you have a data collector?

i'm with JB--

GENERALLY ENGRS DON'T KNOW WHAT THEY WANT--A 50 FOOT GRID, 1 FOOT CONTOURS IS BASIC, DOES IT MEAN SHOTS EVERY 50 FT--NOT NECESSARILY--A GENERAL FIFTY FOOT GRID IS INTERUPTED BY FEATURES AND ANOMOLIES IN GRADE--I FIND IT BETTER TO CONSULT WITH ANYONE THAT HAS A GENERAL SPEC AS YOUR STATING AND REWRITE THE SPEC FOR THE PURPOSE, CONDITIONS AND FEATURES APPARENT--TDD

Ask the architect/engineer what software he is working with and about some of its capabilities.

I did a topo once that had to be on an exact grid for the software to work the data. I computed an exact grid, shot my topo in stakeout mode and assigned elev to the computed grid. Time consuming and a waste these days.

Tell him what that will cost opposed to random shots and he will get up to speed with how is is done.

Bottom line, if that is what he wants, let him pay more for that extra work.

That is what you call a Prescriptive Specification. It is telling you how to do the work; the results are their problem. Caltrans does this with pavement, do it like this, the compaction results are our problem.

They should use a Performance Specification, talk about what they want to achieve leaving up to you how to get there.

When you take a job, you are bound by the specs of that job. So the grid should have been included in your bid.

You can extrapolate the data or you can shoot the grid.

I have in the past precalculated angles and distances from a traverse point to locate the grid intersections to avoid laying out the grid as a seperate task.

That's the way I'd do it. If you know how to effectively survey breaklines and model a site, there should be no issues with plopping the grid on afterwards. In Civil 3d I can do this in seconds.

Thanks gentlemen.
I'm going to call the architect tomorrow.

> All I have is a manual total station.

I use Trimble Survey Controller and would do as Steve suggests. With your equipment you might topo it by the pacing method, create a DTM, then create points for the deliverable from the DTM at the theoretical grid points.

I can just hear the attorney now, after something goes wrong with the dirt quantities (and somebody is always unhappy with the dirt quantities):

Attorney: Let me get this straight. The contract called for a 50-foot grid, you signed and sealed a survey drawing showing elevations on a 50-foot grid, and now you are telling us you didn't actually take elevations on a 50-foot grid?

Surveyor: Well, yes, but I took lots of shots and I'm sure the 50-foot grid elevations are accurate.

Attorney: Just to be clear, you did not take any of the elevations on the 50-foot grid the contract specified, so in fact you cannot testify that any of those 50-foot grid elevations are correct because YOU DIDN'T ACTUALLY TAKE A SHOT THERE (with a sneer in his voice as he looks at the jury).

Surveyor: Well, yeah, but...

Take it from me, doing topos for architects is an old specialty of mine. Chances are his contract wording is a borrowed from an old architect firm he used to work at where they borrowed it from an engineering company that one of them worked at. And that engineering company just dreamed this arcane rule up because they got burned by getting some bad topo from somebody. Chances are that they don't care diddley about how you obtain the topo, only that you do it and do it right. The only instance in which that would matter is if on the deliverable they desire spots shown on a 50' grid. If that's the case, then go ahead and take the shots where they want them. Otherwise, just shoot the breaklines, the summits and sags, and whatever else you need for an accurate TIN.

Still, I would just pace them myself. You have to remember, I will bet that the reason they have this rule in their contract is because somewhere somehow, they got burned by getting a bad product. The antidote to that is to give them good product. There is no substitute for competent, accurate topo.

With all this being said, and in any case, I would talk to them and get an idea of what they want from you. Find out if they want a digital TIN or paper-copy contour lines. Of course, I think it's best to get all this straight before you contract....

Stephen

This is why all Attorneys are a-holes.

A-holes and their irrelevant stupid questions that the Judge allows.

This is another reason it pays to have specific standards in your state. You can specify the work will be performed to the standard. In Illinois we have a standard for topo. Most people will accept that.

The grid goes back to the days of a chain, a field book, a scale, and a level. It really makes no sense today with modern technology. That said, most current Civil/Survey software today will allow you to create a grid from your the tin you make from your breakline shots. So if they insist you can do it without actually doing it in the field.

I will use the latter method to create a grid for earthwork staking, but now with machine control becoming more popular, I'm really not sure what the value of a grid really is.

So true Marc. To perform an accurate topo a 50 foot grid means nothing more than no shots will be more than 50 feet apart. To shoot strictly a 50 foot grid and ignore any breaks between the grid intercepts is absurd.
We actually had a job sent to us that the client wanted us to "blend into a previous topo" performed by our firm. The new data was shot on a 1,000 foot grid. They could not understand why we turned the job down.
Remember, "The Devil is in the details" and you cannot get ANY detail by taking elevations soley on a grid. Just shows that the client does not know diddley about topos.

"Listen to what they want then give them what they need"

Jack Little LS 2883 told me that a long time ago and it has never failed.