Measuring HI

I measure to the bottom notch on the S6.

For typical work I tape to the horizontal axis mark on the side of the gun, then cut 0.01'.

You could always just drill a hole through the bottom of the instrument and plunge the scope.:-D

I was just thinking with laser plumb and all the technology out there why isn't there a TS with reflectorless out the bottom to measure the height?

Would you think it pointless or something that would be a benefit?

I'm just thinkin and drinkin. But curious nonetheless.

They may have them and I've just never seen one or it may be a waste to even have such a contraption.

John Giles, post: 335353, member: 57 wrote: How do you do it? What do you use to measure the height of the instrument?

This is not the point of my thread but I never measure HI, ever.

The point of my thread is that it puzzles me why don't they have a TS/GPS that measures it's own HI with reflectorless? You would use that more than the one on the scope. Or do they have them and I just haven't seen one.

I use a Keson Pocket Rod to measure from the point to the marks to on the side of my total station. I've had the pocket rod for ever. Some where from the mid 90's. I use fixed height GPS rods. I measured the height of each rod to the antenna reference point when I first got em, so I use the same height for each rod and antenna each and every time. I do have a laser plummet on my total station. I have though for years a laser measuring meter to the setup point would be cool. I don't measure HI's when doing most rural boundaries, but if it's for an engineering firm, or if construction is a possibility, I do run elevations. Nothing worst than being asked for a topo after the boundary was run.

Actually there is one in the market already

http://www.horizon.sg/wp-content/uploads/2014/02/EZ-Height2.pdf

I use the ol' put the TS at the same level as the BM technique when running elevations. That way I don't have to measure HI. I then carry the elevation on the TP's and BM each time. Only have to worry about HR if we need to raise prism to get a shot.

Looks like somebody has made a TS to measure HI. Cool. I'll have to wait about an hour for my slow internet to download the PDF.

John Giles, post: 335364, member: 57 wrote: I use the ol' put the TS at the same level as the BM technique when running elevations. That way I don't have to measure HI. I then carry the elevation on the TP's and BM each time. Only have to worry about HR if we need to raise prism to get a shot.

Looks like somebody has made a TS to measure HI. Cool. I'll have to wait about an hour for my slow internet to download the PDF.

I don't understand what you are talking about? Please explain you method.

In the early days I brought my hi in from a remote point just like differential levels. The taped height was a,rough check. That procedure never caught on so I use the keeson or a good tape.

I shoot the BM from TP1 with the TS and set the data collector as shooting BM with 0 HI. I then get a traverse on TP2 and shoot an elevation to it. I also get another shot on a temporary BM. close to TP2.

I move up on the TP2, shoot the temporary BM near TP2 and backsight on TP1 storing the elevation and then get another traverse as TP3 storing the elevation.

Since I have the BM on TP2 and TP 3 I just keep using them as BM's along the way. I carry the elevations on the traverse points instead of measuring HI. I only have to adjust HR if I raise the rod to get an elevation.

Everything in the Data collector thinks my scope and the prism are at ground level this way. No HI needed.

I will say I discovered this way on my own. I'm sure others use it but I just figured it out on my own. My old boss was big on levels. Me not so much. My old boss didn't believe me so he checked me one day on a job I had to carry elevations on with a level without telling me. Maybe I just don't explain it good enough. He was alright with it after that when everything checked out.

Curious how you would handle forced centering, closed or open traverses?
What happens at street corners?
I gather read 2 forward points, setup on one for horizontal, correct instrument to elevation of second mark?
Do you then have separate elevation control to your horizontal control?

How would you trace elevation errors/ differences discovered later?
How would you ever know the elevation of your setup point?
I make stations part of my DTM.
Often I survey past a station then setup and check a previous point or two, but at least I have a genuine elevation for my instrument setup and any cranky heights shows up in the contours.

It sounds like extra work.
I can see your reasoning, but have my reservations.

To answer question, I'm like Jim.
Setting at HI around 1.65 to 1.7 there is little correction (3mm) for non vertical measured HI.

I carry a BM on every traverse. I only have to take a separate horizontal location and vertical location on the first traverse. From there on out I have a vertical to pull from on each traverse as I move up. TP2 has H/E and TP3, and TP4, and so on. Each traverse carries the elevation. Instead of measuring the HI, I just shoot the traverse as a BM and store the new point on top of the old point. point 2 is point 2002 and so on. I can carry horizontal and vertical at the same time without having to measure HI.

I then go all the way around and can close out both horizontal and vertical. Since I shot an elevation to TP1 and TP2 at the start.

It's a matter of shooting the backsight twice. Once for horizontal and the next as a BM. All the elevations are carried on each traverse.

Ok! I don't think I'll venture into that anytime soon. Elevations on each and every traverse point, and elevations on every side shot. I've got enough problems keeping up with things. HI's and HR's are good with me. Simple is good.

It's exactly like measuring HI. You know the elevation of the TP anyway so you are carrying a BM as it is. You then have to measure HI to get the elevation of the TS. The way I do it you don't have to measure HI You just carry the elevation from the previous TP. You are working from ground level. No need to measure and adjust a little because the TS is right on top of what you are measuring to. To me it's easier. But I may be wired wrong. You carry the elevation on every TP as it is you just adjust it by measuring HI. This way there is no HI to measure.

My way seems easier to me. But then again. It's the way I am used to doing it. No HI no HR (unless you raise it for a shot). Just shoot and go.

You are doing fine, John. Don't let the corporate types dim your sights. What you are doing is fine if it works for you and it produces correct results. Each of us has a slightly different approach to what we do. Almost all of it is OK.

I use pocket tape.

That Horizon system is a game winner, gonna have to Redneck Engineer and Retrofit one of those gizmos fer sure.

John I'm not saying what you're doing is wrong. I'm set in my ways with that that works for me. But it does seem that you're taking a traverse shot, than an elevation shot. But what of side shots. Do you take a side shot, than an elevation shot on every point stored?

After the first shot where I do have to take two shots so I have an elevation nearby. I only take one shot to give me direction, distance, elevation.

The main difference is I tell the data collector my TS and prism are right at ground level. As long as I don't adjust the rod up any, the data collector sees the information as though the TS and Prism are at the same height and the rod and legs are underground to the DC. Even though in reality they are not. At each point when I take the BM shot I am resetting everything to ground level. No need to measure HI or HR.

On backs sights I take a BM shot that I put on the previous TP which resets me to ground level no matter how high the TS is above ground and I put in my back sight. But then on side shots and traverses (after the initial two shots for the first traverse) I only have to take one shot just like normal. Only my HI and HR are at zero. I'm flat on the ground in the data collector.