Is this the right place to setup and topo this creek bank? There is really not much choice. I did the other bank from where the gun is and now need to do the opposite bank.
[mp4] http://www.highterra.com/mp4/TunnelOutlet.mp4 [/mp4]
LRDay, post: 330685, member: 571 wrote: Is this the right place to setup and topo this creek bank? There is really not much choice. I did the other bank from where the gun is and now need to do the opposite bank.
[mp4] http://www.highterra.com/mp4/TunnelOutlet.mp4 [/mp4]/blockquote>
Where does that monster culvert go to?
What's that clear stuff in the creek?
rfc, post: 330811, member: 8882 wrote: Where does that monster culvert go to?
It's the outlet end of a 7000 foot long tunnel through the mountain. They are doing a rehabilitation project and needed both ends topo'd. The tunnel brings snowbank water from the Colorado River basin into the Great Basin. At this time all the snow has melted. When I got in the end of the tunnel a bit I could see a very small light (probably the other end). So it's straight. It was built by the Bureau of Reclamation in 1937. My data shows the outlet invert at 9677 and change feet. The only practical way to do it is GPS and the Geoid Model.
Dave Karoly, post: 330813, member: 94 wrote: What's that clear stuff in the creek?
Water, but I still wouldn't drink it unless there was no other source. Pretty much how all the mountain streams are this time of year.
Nice video
Since you can see light at the other end you could always put a prism there and shoot it directly for a check
I am supposing that you are taking a shot down the tunnel to orient your topo at each end......
A Harris, post: 330826, member: 81 wrote: Nice video
Since you can see light at the other end you could always put a prism there and shoot it directly for a check
I am supposing that you are taking a shot down the tunnel to orient your topo at each end......
I'm using a pair of OPUS and static processed GPS points at each end to place me in a coordinate system for the location. I ran 24 hour sessions between the pairs and also a cross tie between the ends. I'm confident I'm within about a cm horizontal. The vertical is the question. Unless I run one heck of a level loop over the top of the mountain I'm totally dependent on GEOID12A. I'll discuss it with the engineers but I think the GPS elevation is good enough for their purposes. I've thought about shooting through the tunnel but I don't think I'd get any better results for the slope of the tunnel. Also they can only choose available pipe sizes to put in the tunnel and the biggest one they can get in there will probably be it. My measurements indicate just a bit over a 0.3 feet slope per hundred feet, I'd bet that was the original design value. They have not found original plans that give the slope.
I did another similar tunnel about half as long a few years ago.
Great situation for a laser scanner.