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Surveying; Leveling2

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Surveying; Leveling

(OP)
I would like to ask a few question for levelling. Is it even possible to measure the height different at the same location? For example, I want to measure the height of a tree at the bottom and at the top of the tree using levelling. Is this possible? If so how would one do it. (Automatic levelling)

Thanks

RE: Surveying; Leveling

This is probably better placed in the Civil/Environmental Engineering sub-forum (though arguably a lot of the sub-forums here fall under 'civil engineering'). Nonetheless...

A fundamental purpose of surveying is to be able to create a 3D coordinate system. If you wanted to measure the height of a tree then you'd probably be better off using a theodolite to measure the angle from the bottom to the top. You'd need to measure the distance between the theodolite and tree too (correcting for any change in level of the ground).

An undergraduate-level textbook on surveying will definitely contain the procedure (it's all just trigonometry!).

RE: Surveying; Leveling

(OP)
Hi LRJ, thank for your reply. I thought surveying would be in geotechnical but it appeared that I was wrong. Personally, I don't think that automatic levelling can be used to measure the height of a tree since the top and bottom parts of the tree are located at the same location. While levelling takes different in height of the ground between two locations.

RE: Surveying; Leveling

Why does it matter if the x-y coordinates are the same if you are measuring z? It's trigonometry: if you have an angle and distance then you can find out the height.

Just to reiterate: I recommended using a theodolite.

RE: Surveying; Leveling

The two shadow lengths should be measured within minutes of each other to increase accuracy

Then cross multiply

RE: Surveying; Leveling

They probably have an App for that. Or get the 7th grade math book from a local school. Then retake your survey course.

Richard A. Cornelius, P.E.
WWW.amlinereast.com

RE: Surveying; Leveling

Because a level is intended to look along a horizontal line, I can't think of a way to measure the height of a tree with one unless you have a hill or a structure nearby almost as tall as the tree. Then you could work your way up the hill with back sights and fore sights to a series of turning points until you eye is as high as the tree.

RE: Surveying; Leveling

climb the tree
drop a plum bob down, hold the top at the top of the tree and make sure it hangs vertically without hitting the trunk
use the level to sight to the plum bob
measure the length of the string
add in the height of the plum bob from the ground

from that you can establish the elevation at both the ground and the top of the tree

with a tall enough "rod" you could do it without a plum bob

or use a theodolite

RE: Surveying; Leveling

Check with Forestry Suppliers. They sell nifty little devices to do exactly what you want and they are not that expensive.

I am not affiliated with Forestry Suppliers and will receive no benefit from this referral....I just get their catalogs and I have purchased a few items from them!

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