I would be interested to hear how much field time different people would estimate to do a field topo of 51 acres. Not really the price, as each of us have our own costs that vary by a lot of factors, such as location (i.e. wages, equipment), etc. I have already priced it and started the work, so whatever anyone says won't influence the project costs.
Many may mention fly it and do it photogrammetrically, but that is not an option, nor is lidar. It needs to be done by the end of this month (leaves still on), client wants it to be field topo'd. 1 foot contour interval, to be able to compute the base surface for spoil volumes to be added later on top of it. Yea, I know, why not wait until they clear the trees, but that is not an option either.
I walked through the site, and there are old man made ridges 20 to 30 foot high in the woods, which I believe are piles of slag dumped from nearby mills many years ago, although by now they look like natural ground (see 1967 imagery). The woods are thick with underbrush (briars, etc), typical Pennsylvania regrowth.
1938 imagery:
1958 imagery:
1967 imagery:
2010 imagery (notice the marcellus shale drilling pad to the left):
Here are 2 foot contours from a 2006 statewide lidar project:
here is a dem from the 2006 lidar survey:
A 3-D view of the DEM
They want to dump 350,000 cubic yards on the site.
25 days..
My first question is what scale do they want the final product at. Based on that, I would estimate linear feet of line, if we were to grid the site. Your estimate should be less than that. Travel time and access will also be factors.
3 weeks field doing daily downloads each night and connecting up the breaklines. 3 days office afterwards.
Scale was not specified, but I would say it should be 1"=40' or 1"=50'. I don't think the scale is the controlling factor, the contour interval is the critical item in my opinion. Yes, there will be a dgn created with contours and breaklines, but the main purpose is to create a base surface to compute payment amounts for quantities of spoil dumped there (Upland Disposal Area, 2-10 and table 6-1 in EM 1110-1-1005). Because there is a lot of undulation (as seen in the dtm and contour map), we will have to scour the area pretty well looking for tops, toes, mounds, breaklines, etc.
My plan (for the woods) is to start from the outside perimeter, and traverse up each drainage feature (swell, ravine) and pick up toes/tops and spot elevations, leaving traverse points behind. As each junction is reached with a branch drain, set a point there to similarly go up that. After we do all that, we can see where extra survey is needed and go back to fill in. Fortunately it is pretty close to my office.
GPS in these woods is not possible, and even traversing will be difficult due to underbrush. Of course this would be a lot easier in January, but someone decided they need it NOW. Steve, you know how the engineers can be, I am sure nothing will be done here for months, and when they do, they will first clear the trees and in the process probably change the ground surface somewhat. But this is what they want, in fact it overrides the shutdown (i.e. is considered critical).
bu, bu... buu.. but it's raining !
:'(
> bu, bu... buu.. but it's raining !
>
> :'(
We haven't had enough rain in three years to amount to much, so we just say it like we do in the oil patch, some days are wetter than others. 🙂
We didn't have a rain out the entire year of 2011.
One Foot Contours
Mean that 90% of test points will be within 1/2 foot. Usually, these tests are made with random profile lines that do not necessarily match where you surveyed. I would be nervous about how strict they were going to be with QC.
As a surveyor who spent most of his career working for aerial mappers, I would argue that a ground survey just can not beat a low fly LIDAR approach for accuracy, price or schedule..... But that is not what you asked.
My WAG would be 250 2-man crew hours for the field. No guess on the office... too dependent on your procedures.
Anyway, John, congratulations and good luck.
> I would be interested to hear how much field time different people would estimate to do a field topo of 51 acres. Not really the price, as each of us have our own costs that vary by a lot of factors, such as location (i.e. wages, equipment), etc. I have already priced it and started the work, so whatever anyone says won't influence the project costs.
You are probably looking at about 3000-4000 shots at a rate of about 200-300 shots per day if the brush is heavy. So about 15 field crew days. Client is in a hurry so you can pad that.
I allow an extra hour per day for the party chief and office survey tech to deal with data downloads. A half hour each.
For a job like this I'll allow 4 hours of office tech time per day of field time.
Then 10% of the total of everybodys time for PLS supervision. This is supervision only. Any time the PLS might spend actually mapping, or writing reports, etc. is Office Tech time.
John,
Years ago I was hired by an engineering company to help out with large topo in northern Idaho. The state was going to reroute a highway out of a valley to the top of a ridge line. All of the engineering was done from aerial mapping in extremely heavy timber and they did not seem to be worried about balancing the earthwork out. Just before the let the project to bid they realized that they would need a good DTM for pay volumes and of course needed it last month. The real kicker was that they wanted it done before they cleared it. I was one of 4 or 5 crews sent in to get it done and it took around a month. Getting 100 shots in a day was good and that was with having a guy cutting every tree that did not have a market value. It was just typical that they absolutely needed the data before they cleared the trees and one crew could have completed it in a week. What a way to spend November in Idaho.
As a wag, I would say about 3 weeks with a 1 person crew and a guy with a chainsaw.
10 days. No doubt about it. Just me, my partner, and our S6. I'd like to have 15, so I only had to work till 2:00 each day, but I could definitely do it in 10 for the right price!
I am currently working on a topo of an approx. 46 acre school property. Its very irregular in shape with lots of parking, curb and gutter, concrete, buildings, 4 ball fields and a blooming million underground utilities. We just finished day 18 with a two man crew using a robot. We probably have 4 more days to finish the topo and currently have just a bit under 12,000 shots. I typically take about 600 shots per day. Some days only 400 and other days 750-800 depending on the area. Its beginning to get a little monotonous. Ten pairs of GPS control points were established first. We have about 40 control points that we set with the robot after coming off of the GPS points to get all the nooks and crannies between buildings and such.
So, depending on many factors, each project will be different. This one is typical for a high school in a mid sized city. Rural areas won't have as many shots, but you cover more ground per shot. The school tract has no vegetation to cut through. Each site is unique and hard to compare with similar sized tracts.
Me. "What's the difference?"
T.C. Carroll "It's the difference between right and wrong!"
A view from this side of the pond.
I'd estimate at about 12-14 field crew days. Obviously it depends upon whether the underbrush is full depth or mainly around the edges of the tree areas.
The site looks a lot like sites I've had in the past which were going to be used for filling - in fact I've been down on one last week dragging my way through thorns.
Where the client is willing I've found it better to get as accurate a plan as possible under the circumstances and then go back once the site is cleared. However, even if the site is "reshaped" during the clearance the overall amount of material on site doesn't change; it's just redistributed into slightly different shapes in the vicinity so calculated volumes are still OK.
That does mean that once the fill contractor starts he will disagree with the site survey you have done!
Existing lidar contours don't look too bad from here. But i guess you'll need 2 2-party crews to get done this month.
I'd be thinking a week or so max, using my ATV wherever I could. Some robot, some GPS, lots of walking. 60 acres isn't that big and 1 ft contours isn't that tough to obtain, especially on several steep slopes. Just pick up the break lines and move on. Why make it harder than it is?
But if Ted was still around he'd knock it out in 2 days without even drinking water..... :~)
> But if Ted was still around he'd say that he could knock it out in 2 days without even drinking water..... :~)
Edit correction
glad somebody has a sense of humor....
BTW, whatever happened to Ted? His bantering was certainly entertaining if nothing else, with all due respect.
> We just finished day 18 with a two man crew using a robot.
Stacy, just wondering what the second person does?
I was right in line with Norman's estimated time.
The only change I would make would be a requirement of one of these:
being used to clear some lines in the denser briar areas to allow for ease of access.
Not long ago, I was surveying a new division line through a farm. Most of the land was clear, but after crossing the creek, they had not used what had been a very nice pasture years ago for so long that it was an overgrown mess.
I started out with a gas powered pole saw. After seeing how slow going that was, I called a friend who has the equipment linked above. I was guessing it would take me all day just to clear a small foot path through. Probably would not have a very visible line after either. He cleared the entire area (20'+ each side of the line I needed) in under 1 hour on site. Much better visibility, easy access, and set metal fence posts along the line to mark it - WELL WORTH THE MINIMAL COST HE CHARGED.
I actually hired someone with the brush clearing attachment on a bobcat to clear my property right before construction. I now keep it clear with an ATV and a pull behind brush mower.
But no, that wouldn't work out here. We have two days in so far, i will take some pics tomorrow of what it is like.