Best practise for surveying boundaries?
It means that CORS points have a velocity. It varies depending where those points are.
Look at a datasheet and see the changes to any HARN or CORS point over time.
Once a project is controlled, it becomes irrelevant what OPUS or CORS is doing. From the moment control is established to the time the project is finished the numbers on the control points are fixed and not changeable unless they are disturbed.
@fobos8 there is no measuring tool in this profession that doesn't include some type of error, whenter it be systematic, compensating or operator errors. The perfect examples are not frequently checking and adjusting instrument calibration, setting the proper ppms & temp or just plain operator errors.
Each piece of euipment has its benefits and detriments. The key is knowing which methods and equipment to use in any given situation or conditions on the work site. Being able to achieve the desired results, no matter what equipment is used making the proper adustments and using the propper settings is what makes us the experts.
One thing that strikes me though is that you advised a potential client that another Surveyor was doing it wrong by using GNSS equipment on boundary work. Without being able to prove that the other person was producing gross errors based on the methods employed, you've crossed a certain line of professional ethics based on personal opinion and not fact.
I was trained old school and for my own reasons, I will not allow my VRS RTK kits to be used for certain things, not that the use of it would be wrong but because I need tight vertical information on certain projects that I know will be quickly moving on to design and construction projects. I am pretty confident the those of us owning total stations and GPS/GNSS equipment are well aware of what our desired results are required and which piece of equipment is needed to achieve them.
In the US, the objective is to locate monuments, many set with very old tools, with tools that can report precision adequate for subsequent surveyors to retrace the same monuments. I don't know about the UK but when US surveyors use high precision tools to change the position of existing monuments, (pincushions) they are 100% wrong and completely illegal
I would add that i know nothing about survey law in UK but I visited the UK some time ago and loved the country and the people!