- SPECIAL REPORTS
- THE MAGAZINE
The fog was as think as a brick this morning heading to work. You could not see 50' in front of you and I almost decided to wait it out at the house, which probably would have been a good decision but with my days dwindling down then I went ahead and risked the drive.
The dispatchers said that today rivaled an ice storm for reported accidents this morning. Everywhere I turned I saw an accident and a police man trying to sort them out and get them on their way.
Fortunately I arrived without incident and Michael and I headed out to do some inverts on a sewer design.
Some sewers are funky and some are extremely funky. This one fell in the later. A 12" and 18" in and a 36" out. Flowing like niagara falls this morning.
It was foggy but the steam coming out of that SSMH along with the olfactory sensations is not something that I am going to miss at all.
The jobsite is down in a low lying area and not really near any poor parts of town. Vandalism is not related to poor and in fact is probably higher in the better parts of town. The poor understand how much something costs to repair. The rich just don't care sometimes because they have no idea of the value since they have been raised with a silver spoon. (Rant Off).
Four pieces of motive equipment that looked like this after the weekend. The wood is to protect anyone from climbing in and getting cut on all the broken window fragments.
We managed to do all our work without incident.
We did have an interesting bit of science involved though. We use our Topcon Hiper hooked up via a modem to get a single line base corrections and I like to see what sorts of results result from odd inits. Generally, we get 0.04' when using our normal base set up on a fixed point locally and we have found that 0.06-0.07 is what we get on our IP base to get good results.
Today was very foggy and the trees around this manhole were saturated with dew so I did get a fix but the stats were 0.10 to 0.20 fixed. I took a dozen of so shots with each fix then we came off a local BM with our conventional level to actually put an elevation on the lid and the inverts.
I also shot the BM with RTK with the same 0.10 to 0.20 fix.
The BM was done with static several years ago and also has on OPUS-S on this point. All very close.
The RTK was 12.0' off...That's right 12.0' on both the BM and the SSMH. I've never seen this much . I knew that it was going to be bad but have never seen one this bad with a fix.
All the bad shots were within hundreths of each other. Very precise but the accuracy was not worth beans.
Not chronological in my post but were returned at the end of the day when the trees had dried and the sky had cleared and got our normal 0.07 fix. The elevations matched the known elevations on the BM and the SSMH within hundreths.
I only point this out to show that the difference in a fix on our Topcon from our normal 0.07 to 0.10 or more means that the position is very suspect. This has been repeated over and over but I don't think that I have made this point.
Stats are important but they are not often indicative of the actual results. This would apply to any RTK system. Almost without fail if we do not see 0.04 with our normal base or 0.07 with our RTK IP base then even if fixed we have a real chance of a bad integer fix.
It is not as bad on the horizontal but is just terrible in the vertical.
So anyway we finished up late, about 12:30, before we stopped for lunch at one of the chain resturants. We usually eat a bag lunch but with only a couple of weeks left then I'm enjoying every day. We stopped at a Sante Fe which has some pretty good Nachos Grande, peanuts and some very attractive ladies waiting on the tables.
Boom! The walls rocked and two booths splintered. Thankfully neither was occupied. It appears a Chevy had decided to make a new drive through in the side of the building. Not on our side though.
I got a picture on my cell phone if I can figure out how to download it. :)
So next we headed to the Holiday in the Park to set up some points for this springs return of the Viet Nam memorial. It's not THE wall but is a traveling wall that has been to Lawton a couple of times. It's a replica of the real wall. A couple of hundred feet long and with an angle of 172 degrees in the center.
We set a 30"x5/8" with cap for the swivel point and are going to do a OPUS-DB on it tomorrow. We also need to do a land change plan on the entire half section so we are going to do RTK tomorrow to update all the new roads and parking lots. They have added a ton of impervious cover so we need to survey all that and merge it with the 36,000 other points that we already have in this area.
Parks and Rec is loaning us one of their Gators to use and the Sanitary Sewer Technical Division Survey Tech is going to get some training from Michael and I on line coding.
The survey tech, Richard, has the same exact Topcon system as we do and their office is just now learning to use coding and EP to reduce the data.
I'll let Michael do most of the training tomorrow as he will have to work with Richard after I'm gone.
We did the recon on the area today, so while we walked/drove around then we tossed out our Hiper on the swivel point. Only got 30 minutes but I sent it in for an OPUS-RS and we shot it with RTK also before we finished up.
A couple of extra checks for tomorrows OPUS-DB session.
But I need some help. With OPUS-DB you get to name a new point.
This is for the memorial so the name VietNam comes to mind but also the name Brunner. Duane was my mentor at the city and was also a surveyor in the military. An exceptional 82C and he did some tours in Nam at fire bases.
Any other ideas?
To read the rest of this thread go to www.i-boards.com/bnp/pob/messages.asp?MsgID=1499612&ThreadID=141449&IsResponse=False#1499612.