Trying too find height from total station to height of power pole

You want to end up with height above ground??ÿ I don't see you say you have measured up from the ground to the mark. And at first reading your adds and subtracts don't sound right, but I'm not sure.

Draw yourself a diagram to make sure you have everything properly accounted for, and the adds vs subtracts correct.

This youtube video explains it pretty well.

So the guy who taught me told me to use the reference point I made on the pole pole and didnƒ??t need to measure my instrument. But everything Iƒ??ve read says I need too so thatƒ??s why Iƒ??m reaching out. Iƒ??ve also watched this YouTube video but was told that the VD distance on the Trimble is your straight distance? I am now thinking everything he said was wrong.?ÿ

It's not at all clear what exactly is being measured here, and what it is being measured relative to...

Do they want the height of the pole above ground (at the pole)? The catenary (sag) height above ground at the sag point? Difference between sag height and height of line attachment at pole?

Any and all of those measurements can be observed without setting up directly under each pole.

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Keep in mind that if there is no control network throughout the project area, and everything is being measured off of random setups, the measurements from different setups will have absolutely no relationship to each other.

I am trying too find the height of the point where the wire is attached to the pole to the theodolite. I am trying how to use the single span method on moose o malley( well the free version of it) we normally use targets for this application but just recently received the software and want to make sure Iƒ??m doing it right. Any suggestions would be helpful.

VD is vertical distance, many total stations have the option, going back to the very early days of total stations, to display VD (vertical distance), SD (slope distance), HD (horizontal distance). Depending on your instrument you can do this to a reflector or reflectorless to the pole itself. You said your VD was 210. That means the height of the pole is 210 feet above the instrument, a very, very tall power pole. If the pole is plumb, it's a simple calculation to measure a point above the ground on the pole, turn an angle to the top of the pole, then it's very simple trig to get the distance between the measure point on the pole and the top.

Perfect just wanted reassurance that the VD distance was correct. Thank you for your time.

You say you setup about 200 ft away and measured VD (vertical distance) of 210 ft. That is looking up at a 45 degree angle and hard to do on most instruments. Are you sure you are not measuring the slope distance? Do you really have poles 200+ feet tall? There is just something about it that doesn't sound right.

James

Assuming you have a reflectorless machine.?ÿ Hit top of pole or attachment point or whatever you need.?ÿ Hit another point on pole from same setup at a point close enough to ground you can measure it easily.?ÿ Compare vertical distance of top to vertical distance of point near base.?ÿ Subtract to get the true delta then add the distance from your low mark to the ground surface to get total delta.?ÿ This would work on a standard single pole but not necessarily on a "Y" or "H" type situation as your horizontal measurements would differ depending on how you are situated.

@self-taught-surveyor VD in Trimble software is Vertical Distance, SD and/or HD are the values you'd want to use for this method although with that equipment you wouldn't really have to use SD or calculate the VD values as shown in the vid.  They would be present in your survey shots and you could just scribe them and use them to do the final simple math.

Like the others, I don't understand what you are trying to measure. You say, "sag program", and the sag is the most commonly measured part of a power line. Are you trying to measure the sag? There are very few instances where the height of a the actual pole above the ground.

There is a much easier way to measure the sag. No total station required. Are you working alone??ÿ

?ÿSarcasm font being turned on::::::::::::::::::: First thing you do is find you the longest cane fishin' pole in the world, then you sort of reach up as high as you can, and then..................?ÿ

Naw, forget that.?ÿ You'll need a new cane pole every time.

Let me try to answer the question that was asked:

I assume all values given are positive. It is important to note whether the VD is positive or negative, above or below level.

1. The top of the pole is 210 feet above the first instrument setup.

2. The mark is 3 feet above the first instrument setup.

3. The instrument was moved and now the mark is 2 feet above the second instrument setup.

4. Therefore the instrument is one foot higher.

5. And the top of the pole is now 209 feet above the second instrument setup.

my sketch:

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I'm still hung up on the 210' tall power pole.

I can see a total station sitting in a valley locating a pole up the slope getting that tall above the instrument, but above the ground?

And I am still hung up on being 200' away and shooting 210' up. That is a very difficult, or impossible shot on all the Total Stations I have ever used. Also why is it called a, "sag program" if it is not for finding the sag??ÿ

Can you confirm that you are actually measuring poles that are over 200' high? Most poles in North America are 40' high. And most have never seen a pole over 120' high. This is throwing every one off.?ÿ

If you are measuring an unusually high pole and somehow measuring a vertical angle greater than 45 degrees, Dave has given you your answer.?ÿ

Thank you Dave that is exactly the reassurance I was looking for?ÿ

@mightymoe. Well, it’s probably a Texas power pole.... ??? ??? ??? 

do the poles have airplane warning lights on them?

@self-taught-surveyor

I am still worried you are doing something wrong, how did you shoot the 210' vertical distance from only 200 feet away??????

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