I confess the subject of Lidar is a bit outside the relm of my experience but I'm always looking to learn something new. Maybe why I like hanging out as fly on the wall here so much.
So here's my deal. The utility I work for recently was awarded a grant to build 60 miles of aerial fiber optic cable over some pretty rough country. The pole line that they plan on tapping to hang the fiber was 'mapped' in the 1950's and the mapping is pretty worthless. No detailed information on pole size, span, that kind of thing. No ties to any control on the ground. Part of me was hoping I'd get tasked with mapping a good portion of the route, but being an army of one, I'm afraid I'd be biting off a bit more than I can chew, especially given the time frame they need it in and the time of year.
A few years ago our local government flew aerial photography and Lidar along this route. Does anyone here have the experience working with Lidar data to know if this 'point cloud' can be mined for the pole data we are looking for? I understand the basics of Lidar, creating a bare surface so forth, but can utility pole locations and sizes be extrapolated from this cloud? Would this be a complete waste of time pursuing?
Cheers all! TGIF. ~ Willy out.
My comprehensive knowledge of LiDAR is not vast. But I've done a lot of miles of aerial utility RW and the ground/ boundary data on a number of these projects was developed from LiDAR. That's just the data we were provided.
Of course data is only as good as who put it together but from what I've seen, it's good. We were not only able to determine pole locations, but also attachment heights and pole/ structure top elevations.
When you say pole "size" I'm wondering are you meaning height, or pole class (diameter)? I don't think the data would be able to determine the pole diameter, but we were definitely able to determine location and height. I was impressed with most of the stuff we were provided.
Your experience is very similar to mine.
If the line being flown is the wood pole line then a lot of data can be obtained. If the wood pole line is crossing the line being flown then the LIDAR coverage may not be ideal, if the pole line is passing through wooded areas. The outer limits of the LIDAR will be observed at an angle well off the vertical and some of the signals get obscured - you can't always see the poles for the trees. In particular where the adjacent trees are higher than the crossing line then the number of hits on the conductors is low.
I found it best to specify that vertical and oblique video was taken at the same time as the LIDAR; this greatly helps in interpreting the results. The end product does rely heavily on the expertise of the technician handling the data.
Appreciate your comments Paden and Chris. Thank you.
