GPS or Total Station?

[Oson]

Hello:
I am not a profesional land surveyor but I have been reading a lot about DGPS giving such a great accuracy in the 3 sets of coordinates (x,y,z), I wonder what do we need a total station for?.
Would it be enough to get my 3 readings out of the point that I am interested in, and process that information?.
Will the Trimble R3 give me accuracies in the order of 1:4000 for closed traverses?. What do I buy?.
Thanks
José

 

[IRstuff]

Neither am I, but it would seem that there are still some advantages to using a theodolite.

Consider that the British, in their inimitable way, were able to measure the height of Mount Everest to within 200 ft of the modern value using ONLY transits and measuring chains.

TTFN

 

[IRstuff]

Sorry, clicked submit too fast.

GPS continues to come down in price and increase in performance. Hemisphere GPS advertises an OEM GPS board that has 2.5 m (95%) standalone positioning error and cm accuracy in DGPS mode for less than about $5K. But, it won't measure angles. Now, maybe you don't need angles, so ultimately, it's up to you to decide.

TTFN

 

[icelad]

I am an RLS in Tennessee and the one thing that I know of (in TN) is GPS is not an approved method of describing the property. You still need the Metes and Bounds system to use in the Colonial states. If it was me I would have a much easier time w/ the TS then the GPS because of the ease in not having to convert the GPS to metes and bounds.
Thats just me
John

 

[looksatstars]

the GPS wont work under tree cover or in buildings.

I hooked up the gps to a quad and rode up and down a section of land i needed a topo for. 10,000 elevation shots in one day. It was great.
Its nice to have both systems in your arsenal.

 

[JDEdwards]

I would agree that you need both. I am also located in Tennessee, and I have yet to go to a job where I did not use my total station. If you had to buy one or the other, I would go with the total station. You can traverse anywhere you need to go, with no limits on vegetation. However, when you get into wide open spaces, you would love to have the GPS system. I do alot of construction stake out, and our increase in productivity with the GPS is remarkable.

 

[BRIS]

I have found most surveyors are generally disparaging of GPS which is not surprising since GPS will eventually put them out of work. For most work that we are involved in – utilities, irrigation, river engineering, infrastructure etc differential GPS provides the required accuracy and speed. A GPS system costs 2 to 3 times that of a total station but the extra capital costs can be quickly saved in the operating costs. GPS is no use if there is no sky but with the increased numbers of satellites we have found no difficulty in urban areas. I can't tell you what to buy because our surveyor, who is a convert, keeps this black box technology to himself. I can tell you that the only staff he now needs is a guard to look after the base station while he travels around with the roaming station and that he is able to produce mapping in a fraction of the time that he used to take.

 

[jdkjt8]

Here in California, we use GPS in wide open areas, with no tree cover or buildings (i.e, central valley, the high sierras, desert) - Agree with Icelad and BDEedwards, and GPS is great for taking a lot of shots, so use on big project sites. Alson in Alaska, where I did a lot of professional land surveying - GPS is used for the major outside control network, and then itermediate runs with a total station. There is new software and hardware that is interchangeable, so can go from one system to the other. The key is the data collector, use Trimble, you will not be sorry with the quality choice!