You probably got the tops of the cars. I would be interested if you were to draw a contour exclusion box around the car and see what you get then.
I seem to recall there are issues with paint stripes because of their high reflectivity. I wrote a program many years ago for LarryP to sift through HUGE amounts of LiDAR data so I did learn a little something about it.
You might want to ask LarryP. He may remember. I don't.
It's BAD
Note:
Contours shown herein are Best Available Data.
:-S
I don’t think it was a rod height bust. If the rodman raised the prism and the I-man forgot to change it, then there would be a depression. In this case, there is a hill.
To me, it looks like pre-construction contours. I very much doubt that the aerial photo and the Lidar was taken at the same time. But a car could have been parked in the adjacent space.
"If the rodman raised the prism and the I-man forgot to change it, then there would be a depression. In this case, there is a hill. "
think about that again.......
good call
You are all wrong.
This data came from the govt. And since it did it is 100% accurate. So please adjust your thinking.
Thank You.
A County or City may have the entire jurisdiction surveyed by aerial Lidar methods.
The purpose is not for localized design; one purpose is to determine drainage sheds over a large area. It works fine for that and is a reasonable way to collect the data.
Joe
it's "in the computer" already so it must be right.
A friend had a problem with a private customer service; seriously, that is what they were trying to tell him. He finally got it through to them that someone keyed in the information wrong.
> Just another example of LIDAR proofing gone AFU.
I think that Mike hit the nail on the head. The problem with LIDAR is that if you do not collect aerial imagery at the same time, then there is no way to tell what you have. You are essentially just plotting contours blind.
From personal experience I have rarely found where LIDAR is the best choice for topo work. I would take traditonal aerial photography (aerial imagery with sterescope) anyday.
Of course over large areas LIDAR is usually the best choice as you can effectively collect data at a fast past.
You are all wrong.
I hope people get my humor.
You are all wrong.
Yes, I get your humor. I'm laughing inside, believe me.
My subordinate employee was talking to another agency's surveyor yesterday who was complaining about non-surveyor employees of that agency using hand held GPS to find the boundaries and often being off 100'+. He calls it "precisely inaccurate" because the device tells you where you are to several decimal places even though the post sticking up 3' with signs and flagging all around it is 100' over there.
Surveyors in 1900 probably threw rocks through the windows of the USGS building with notes taped to them about how the contours on the quad map missed a little drainage swale (I see that a lot, this swale can't be here it's not on the map).
Granted, 2' contours is probably too precise for the method used to gather the data.
Also I think Quad map contours were actually run by someone manually on a stereo plotter so there was human vetting as they went rather than just pushing a button on a computer.
oops. your right. reverse what I said.
nm.