Designer- "Yeah- we designed this project off?ÿof the county wide LiDar?ÿ ( State plane US Survey Feet) and the AS-Builts from Project no. ####### ( local metric job) - I think I converted everything correctly so that it's in local Feet- can you go out and get us some ground shots to check this??ÿ" (it's a less than 2 ac. site project)
Me- "Well a couple of things.... I need control to get ground shots- your contractor is going to need control to build this ... and the control from Proj. No. ######## all left town in a scraper can in 2002."
*crickets*
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Please Rankin, not the control thing again. ??ÿ
Reminded me of the college summer school class I took with a room full of foreign students from all corners of the Earth with a Taiwanese professor who couldn't properly pronounce the Greek letters used routinely in our classwork. ?ÿHis English wasn't so hot, either.
All that data manipulation for a two-acre site that now needs field verification and control, so how much did you save by not hiring a Surveyor in the first place? C-L-U-E-L-E-S-S.
Lately I've had a couple of similar calls sans the as-built bit.?ÿ It seems to be a trend.?ÿ An engineer I know keeps using the statewide LiDAR data and GIS boundary for small projects.?ÿ These are usually residential lots.?ÿ I will note that they have not been for design near property lines.
Reminded me of the college summer school class I took with a room full of foreign students from all corners of the Earth with a Taiwanese professor who couldn't properly pronounce the Greek letters used routinely in our classwork. ?ÿHis English wasn't so hot, either.
when i went back to get hours to qualify to sit for the exam, 16 years ago now or whatever, i took a statistics class.?ÿ which, for all intents and purposes, was a "how to utilize microsoft excel to brain on your behalf".?ÿ teacher was a chinese grad student and she was nice as can be but had a terribly poor grasp of english (having been to china a couple times previously, i understood that her english was horrible even for the average chinese person).?ÿ made class a little more challenging for me, as a studious, 30ish new father who was there to get things done.?ÿ all of my other classmates (your garden variety of 18-22 year olds with various levels of ambient BAC at 8 a.m.) had a considerably more difficult time with it. "kuhtOsis" will likely be one of the words i babble randomly when my grandkids come to visit me at sunset village...
but- back to the topic at hand- dealt with the same on a major road tie-in:
?ÿ"your contours don't match ours."
"yeah, figured that was gonna happen.?ÿ give me yours and tell me where you got them and i'll try to straighten it out."
"ok.?ÿ ours are lidar from ."
look at the dates flown - may.
tie in is in the middle of an existing hay field.
best part was i go in and start IDing the contours on the lidar file and every SIXTH line is a major contour.?ÿ WTF??ÿ turns out that for some whoknowswhatthehelltheywerethinking reason a half-foot contour was drawn between each major contour line and the next one lower.
i just emailed back and said "just pay us to go shoot the rest of this 30 acres.?ÿ it'll take a day."
About 15 years ago I staked a long water line for an outlet into a new reservoir. This line was picking up water from wells and holding it in the reservoir which went into irrigation lines and basically weeped into the ground.
Anyway it came from up to 15 miles away through a valley which had up to 500' side walls. The profile line had to climb at the end near the reservoir out of the valley but there was lots of head by then. I staked the route and gathered a profile, sent it off to the company.
A week later an engineer called me in a panic telling me my elevations were way off. He was designing release valves, hydrants and manholes for the system and was up to 40' different in elevation than what I had sent off.
Now me in a panic I plotted?ÿmy profile?ÿagainst the quad, the point where it climbed out of the valley was the big concern and my line plotted along a contour line and fit almost exactly, me being on 88 and the quad on 29, all the other elevations plotted close to perfect. Of course I had checked all my control but the 40' sounded like I might have sent off ellipsoid heights or something.
So I got with the engineer and he tells me that he has DEM data. I say Digital Elevation Model? Yes. Ok from who? Who did the model. Turns out he has no idea, he got it from the internet.
My first experience with DEM from the interweb. Wasn't going to be my last.
All that data manipulation for a two-acre site that now needs field verification and control, so how much did you save by not hiring a Surveyor in the first place? C-L-U-E-L-E-S-S.
Hire a surveyor?!?!? We work for the same department with a widely understood (at least I thought) workflow standard (complete with Gantt charts) of?ÿ?ÿ"1 ?ÿGet your survey" "2 design your project".....
State Plane from a third party, local metric, let me guess,,,,,,a really old job before they finally canned metric.
Then it all converted to local feet, what could possibly go wrong with that?
Hope they know that when you scale those jobs it's really easy to scale elevations; if you aren't very?ÿcareful.
State Plane from a third party, local metric, let me guess,,,,,,a really old job before they finally canned metric.
Then it all converted to local feet, what could possibly go wrong with that?
Hope they know that when you scale those jobs it's really easy to scale elevations; if you aren't very?ÿcareful.
It's for a detention pond- Like you said- what could go wrong?????ÿ Hydraulics has jumped on the band wagon now and sent a laundry list of stuff to check - once we get control established.... who knew....
2 acre pond, the topo could amount to 10 minutes in open ground, seems like a worthwhile expense, almost all of it driving there, setting up, picking up. Unless it's in deep timber or a bunch of detail, then it could take a few hours,,,,,still why not get it right.
I have some community LIDAR mapping, it's not bad, but it can miss .5' to 1'?ÿfor a small site. That's a lot of dirt over 2 acres.