Anyone getting requested to do this lately? We just finished performing a topo on 2.1 acres in an adjoining county and with the offsite topo to edges of asphalt it was about 2.7 acres. On a 10' grid, which was their requirement, it came out to 2000 shots.
There is approximately 20' of relief across the site. 10' grid is overkill in my opinion. 25 would have worked along with catching all of the needed shots that didn't coincide with the grid.
This is my first one like this. They said to get 1' contours, they needed 10' grid. Are engineers now doing the contouring themselves and this is a requirement to make sure they get enough data? Also, trees over 3" with drip line had to be mapped. Did I mention the yellow cats are about a week from showing up on this project?
Someone doesn't know what they're asking for.
Well, he wants, he gets!
what a pain, Kris. I turned down a project where they wanted 5' cross sections, on two mile long jetty's! I thought it was a typo but when I checked with the potential client they said "no, 5' cross sections." I tried to get them to do a UAS survey of it, better data, more accurate representation, but no way.
The terms of the contract were beyond my ability (and interest!)
10' grid on a parking lot? You gotta wonder what they're thinking! More data is better?
Kris Morgan, post: 366022, member: 29 wrote: Anyone getting requested to do this lately? We just finished performing a topo on 2.1 acres in an adjoining county and with the offsite topo to edges of asphalt it was about 2.7 acres. On a 10' grid, which was their requirement, it came out to 2000 shots.
There is approximately 20' of relief across the site. 10' grid is overkill in my opinion. 25 would have worked along with catching all of the needed shots that didn't coincide with the grid.
This is my first one like this. They said to get 1' contours, they needed 10' grid. Are engineers now doing the contouring themselves and this is a requirement to make sure they get enough data? Also, trees over 3" with drip line had to be mapped. Did I mention the yellow cats are about a week from showing up on this project?
There was a formula for gridding a dirt site way back in the average end area days.
100' grid produces x% accuracy
50' grid produces x+% accuracy
25' grid produces X++% accuracy
10' grid produces x+++% accuracy
I think it went something like 100'=90%, 50'=95%, 25'=96%, 10'=96.2%. I'm guessing, can't remember the exact numbers but there was a point where you are just wasting time.
I do know there was a marked increase in accuracy when we started to locate breaklines, and dumped the grid or cross-section methods.
10' is silly for a dirt site, you are just taking meaningless shots to satisfy an anal engineer somewhere who writes up specs like this.
25' should be about perfect, plus all the breaklines.
Kris Morgan, post: 366022, member: 29 wrote: Anyone getting requested to do this lately? We just finished performing a topo on 2.1 acres in an adjoining county and with the offsite topo to edges of asphalt it was about 2.7 acres. On a 10' grid, which was their requirement, it came out to 2000 shots.
There is approximately 20' of relief across the site. 10' grid is overkill in my opinion. 25 would have worked along with catching all of the needed shots that didn't coincide with the grid.
This is my first one like this. They said to get 1' contours, they needed 10' grid. Are engineers now doing the contouring themselves and this is a requirement to make sure they get enough data? Also, trees over 3" with drip line had to be mapped. Did I mention the yellow cats are about a week from showing up on this project?
Preparation for a solar installation?
Kris Morgan, post: 366024, member: 29 wrote: Well, he wants, he gets!
perfect!
a proposal including various methods and various levels of detail (maybe even a sample or two) might make a friend, regardless of which item is chosen from the menu.
We have shot the actual contour lines rather than a grid. That really blew them away.
I've been doing these for maybe 3 years for ADA compliance. It's usually not a 10' grid for the whole topo though. I try to get the engineer to narrow it down to the specific path of accessible travel. Then the rest is about a 25' grid, which is still very annoying. I feel like 50' is good enough for most things.
I have provided clients with data points on a 10' grid (generated from my DTM). And I felt confident of the data provided. I stated ground point information was +/- 0.1'. My actual topo shots were not necessarily on a grid, but on break lines. Actual field shots were no father apart than 25'. If you can't digitally densify your terrain model with confidence, you didn't take enough shots. Just be careful how you describe (or DON'T describe ;-)) your "shots".
Kris Morgan, post: 366022, member: 29 wrote: Are engineers now doing the contouring themselves
A surprising number do just that. Sometimes they ignore the surveyor's contours and create their own. More often they don't get contours from the surveyor. A lot of surveyors don't even deliver maps, just point lists. I'm serious.
Norman Oklahoma, post: 366053, member: 9981 wrote: A surprising number do just that. Sometimes they ignore the surveyor's contours and create their own. More often they don't get contours from the surveyor. A lot of surveyors don't even deliver maps, just point lists. I'm serious.
We have been doing that since the mid 80's for some engineers.
lots of pictures, lots of notes, and all the codes have to be perfect.
The DOT has a book with codes, and it's generally required that all the engineers use microstation to draw their maps with, we send the points and they plug it in and draw.
The biggest issue are curbs and hard surfaces, you really need to turn down the contours to see curb cuts and details.
That seems like overkill, especially if you are shooting breaklines. We always do line work (top of bank, toe, flowline, breaklines, back of curb, face of curb, edge of pavement, in addition to plain ground shots. We can get 700-800 shots in a day on fairly open ground, a little more on wide open, a little less on more covered. Way less in the woods.
[USER=10599]@Timberwolf[/USER] If you did a good job of defining the site just generate spot elevations on the desired grid spacing... we did just that back in the stadia topo and hand drafted contours days, and it really did not take all that long... with Cad it is downright quick. BUT if your field collection is lacking, then you goofed.
give the client what they ask for.
As long as they're paying I will set up a robot and take a million shots if that's what they want.
Somebody is counting grains of sand instead of estimating cubic yards.
I'm not getting off my ATV when I topo.
O'well, mo money in the bank for Kris.....;-)
On these types of projects we perform the data gathering as we see fit, sometimes shots every 20', sometimes every 100' - whatever we feel is required by the existing topography. Add ALL the breaklines, create a surface, create the point elevations on whatever grid spacing the client wants, plot, sign and seal and send it out the door, along with the bill for what it is worth, not how short a time we spent to produce it.
I don't topo by grid. Sometimes I will get a shot every 15 feet if the ground is evenly pitched or sometimes I will get 8 shots in a 10x10 area if there is a swale. With the robot it's easy to just go nuts clicking away.
I also never send my point data with my cad. Just the contours.
Sounds like the specs on those projects were written for lidar or drone. Topographic mapping from low flight imagery.
It was a nice payday for sure and I was able to add a lot of synergy to the project. We have existing gear that's long been paid for. We did the boundary in a few hours and set control. Came back, massaged everything, loaded the robots up with points and my and another RPLS in my office that we work together as a crew, well he started on the South end, and I started on the North end, and by the end of the second day, we were done. We had a bit of clean up the next morning and by Wednesday afternoon, it was gone.
On topo like this with this many shots, I process the data daily. So we quit each day after 8 hours and went back and for about two hours in the evening, I processed data, connected linework, set up the break lines, et cetera. I don't use field to finish and I know it would be faster. Reason is that I can't get even the two other RPLS's in the office to be consistent with field codes, and forget the crews. So I do it like this.
So, when I was finished on the second day, that evening, I had all of the contouring done. I needed inverts on MH's and some other ancillary things to finish up like setting the TBM's and running between them to verify them. Done and done up right. His 10' grid nearly tripled the price of the project and I did it in four full days, counting the boundary and all drafting. Andy, it was a nice pay day and well deserved.