Would You Use RTK Base and Rover. If you knew you had a site wide open and doing grid stake out with a tolerance of 0.10 ft. For HZ and VT. I have tested and proved to myself and my LS that this can be done which would save a lot of drive time and movement of a Robot on a 100 acre site that has multiple things going on at all times. So we might be at North end working in a couple acre area and contractor sais I need X verified on South end. This is a site that its a 30 minute drive around from one end to another at best as no driving on the area of work. I personally have no issues but some in chain of command are a little hesitant. This is truly all dirt and we certify to the o.10 ft HZ VT is all on a grid.
I am also trying to talk them out of exact grid points on a 50 ft grid and go with a more dense topo to the surface for the as-built. But some do not think a surface is accurate enough.
RTK, yes. VRS, no.
I aggree. Vrs in my area has a few issues. Not reliable in this job site area and cell coverage is bad as well. Hood old fashion base and rover on site all day long. Thank you
You should easily achieve results within the given parameters as long as your base is relatively nearby and your GPS is relatively current. Definitely R10 or above (not that R10 is anywhere near current, but it's substantially better than the R8).
Base/Rover for all dirt topo and staking. With Geoid18 there shouldn't be any issue with an R12 for dirt layout and topo. The instrument and levels would be needed for concrete ect. I do know crews doing curb and gutter/pavement/bridge/pipe work with GPS, but I don't recommend it. Actually with newer equipment it's getting very close to being acceptable, I just can't go there.
We do a ton of concrete work with GPS. Of course, if the grades are really flat we'll break out the gun or the level but for the most part, it's all GPS.
A 50' grid is not a good way to create a surface or to check one. Taking shots at appropriate points will always be better and more efficient. Limiting distance to about 50' between shots is certainly not a bad practice. A strict grid though, leaves you wide open to missing important changes in grade.
All ground topos should be collected using breaklines, features, and random topo locations, grid and cross-section topos went out the door long before GPS showed up as a useful topo tool. The increase in accuracy was well measured across the industry. Doing grids or cross-section topo and layout is old-fashioned, counterproductive, more time consuming (meaning more expensive), and less accurate.
All ground topos should be collected using breaklines, features, and random topo locations, grid and cross-section topos went out the door long before GPS showed up as a useful topo tool. The increase in accuracy was well measured across the industry. Doing grids or cross-section topo and layout is old-fashioned, counterproductive, more time consuming (meaning more expensive), and less accurate.
Doing only grids is old-fashioned, but throwing them out entirely for every project will get you in trouble as well. Trying to eyeball every single breakline feature without any observations in between is going to return a subpar product.
Doing both allows for obvious features like tops and toes to control the breaklines, while also picking up the less-obvious topography like shallow bowls and gentle changes in grade that do not stop and start at a perfect geometric line. Nature doesn't only work with breaklines.
If someone thinks they can produce a more accurate surface by disregarding any shots other than what they personally judge to be a breakline - especially over vegetated and/or natural ground, but even on larger hardscaped areas - then I've a got a bridge to sell you in Brooklyn.
If someone thinks they can produce a more accurate surface by
disregarding any shots other than what they personally judge to be a
breakline – especially over vegetated and/or natural ground, but even on
larger hardscaped areas – then I’ve a got a bridge to sell you in
Brooklyn.
Who suggested disregarding anything that is not a breakline?
When in doubt, shoot it out.
ALL yes I understand that about the grid for sure. We do a very tight topo breaklines more dense than every 50 ft. No matter what. But after that is done we have to create a 50 ft grid off of that and re use those same points HZ and just raise them for different layers to certify those points are good. I would prefer to just raise my original surface and as-built it as needed and be done with POINT staking all the time. I believe its just as quick to walk around and check the surface than navigate to specific points and then measure for sure. Might even be better to just re topo and do a surface to surface each layer any areas out of tolerance highlight for contractor to fix. But I have brought all this up and keep being told it will not work and that's not accurate etc..
I have staked conc as well with rtk base and rover especially when relief in design allows. Yes many people are doing this. All over the place. A friend in MS said they would stake pipes and after running levels back through so many times they dont worry about that anymore as its good enough. Now when its flat he approaches much different and uses robot or levels etc. Its good to know I am not the only one who sees the value of todays capabilities with RTK. I mean once you have to wait on line of site or move the robot around a site for line of site you can set a base up and just go anywhere.
I did a topo not long ago out of town. We counted that we would have needed 5 set ups to complete at minimum. I used base and rover and off to the races. So much more efficient and It was wide open so no multipath at all. I went back and compared to other topos on same site for time. All done with robot. We did what usually took 3 long days travel included in less than half the time. We ended up staying the whole 3 days as it allowed me to go and do some other work that was requested.
Yeah I have slowly been weening my crews off of grabbing a robot first. It has taken me a while and lots of proof to prove to the LS that most of the time rtk base and rover are more efficient. Now I always build a network for all control and property corners so I can perform a least squares adjustment and run the reports and such. It become so efficient and once the crews start learning what to watch for besides just pushing the store button and how to set up the control and get redundant measurements it is very productive and rings the cash register as well. So much so they are slowly looking at changing some of the way they bid projects. I did a project recently topo that i had to milk the clock as we got done to quickly and needed those hours.
I would prefer to just raise my original surface and as-built it as needed and be done with POINT staking all the time. I believe its just as quick to walk around and check the surface than navigate to specific points and then measure for sure.
I'd say it depends on the application/project objective.
I'll be first in line to ditch point staking, if there's any way I can. That being said, sometimes it's just the best solution. We do work for soil remediation, and they basically require a survey on the same tight (5-10 foot) grid points for pre-excavation, post-ex, and post-fill in order to certify that they scraped away enough contaminated dirt and put back the exact same amount of clean dirt.
For small sites like residential, it's often easier to just load the points up in your staking list, in order of most-efficient observation, and just run down the list. On larger sites, rather than point stake I much prefer to just have lines across the site to stake to, so you can just stake "to the line" and run up and down getting observations at consistent stations.
Same thing for topos - smaller sites with not much area in between breaklines? Sure, just do random observations at roughly consistent spacing, no need to try and set up a true grid. Large sites with lots of open area? Tie two points to use as a baseline, then either generate lines to offset and follow for a grid, or just stake to the same line and keep consistent station/offset when observing.
Mindless ground topos are really easy when you set up the receiver to automatically take (and automatically store) a natural ground point as soon as that rod is close to level. Heck, with the R12i it doesn't even have to be level, just plant the tip and keep it there long enough for it to take the shot, then move on. No need to even touch the DC.
Yes very true on r12i. It has made me a believer for sure. I was out in field and had a chief with me as we have been down field personnel. He said i will drive you over to get to a point to check in. I said no need I checked in here. He said the robot is set up how did you do that. I showed him and he was like oh I thought the tilt was only for topo. I said well we are doing a topo up here on this construction site about 55 acres for volume. I can live with cking in like this. Of course it was almost the same exact error of a couple hundreths as the rough fly control had anyway. He was in one corner i was running around the side slopes . I said something is wrong with this. I am the old man here ruining around the steep stuff and here you are on flat ground as a young buck. He got me and said you are the boss and with age does not mean getting smarter lol. He is a great young chief. I am just one to never ask anyone to do something i want do myself. So any time i go to the field i make myself take the worst part of the job. Then when i am sitting in the chair at office and they say this is tough i can say just get it done and they do. Yeah i am with you on lines and grids. This site is just one that is ideal for surface staking as- built to a dtm or ttm for Trimble I guess .
