Question re: height of instrument

It's a legacy format from the days of hand-entered data and calculations.

Thank you.?ÿ So it was a handy column when doing the math (instead of a scratch pad).?ÿ Do any surveyors today (who are practicing surveying) calculate?ÿhi or note it in their records, whether on paper or electronically?

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Calculating he instrument height is useful when you have a bust and have to figure out where. There are also times that a level run ties in various points without turning on them. Calculating it afterwards does not help you with a bust while in the field. Typical extra points you might shoot on a level run is every inlet grate, top of casting,?ÿ hydrant bolt?ÿor manhole?ÿalong the way. The field ?ÿcrew may shoot them later with a total station, but guess which elevation is more precise. Such points may become local benchmarks as the project proceeds, such as individual lot as-builts. If the draftsman looks in your field book later at blanks, he/she will curse you. I worked in?ÿoffices where if you calculated something in the office in a field book it damn well better be in red, with your initials in red on every page. There are offices that do a level run on all staked out hubs for curb construction, etc. for cut sheets. Three to four hubs, more if left and right per turn. Yeh, all sights are not balanced, but still more precise than EDM shots. Lastly, you do not always get the choice of using an autolevel.

All your math should be in the field book, and not on a discardable scratch pad.

Paul in PA, PE, PLS

There will be times when you take one backsight and then several shots before taking your next turning point. The HI will make it easier to calculate those elevations in the field. I am entering a set of notes now with about 20 shots per setup. Even if I calculate it using excel, putting the HI in the fieldbook gives me everything I need next time I am on the job.

James

We did do a profile leveling last time, but I still didn't use the hi. I could in theory, but I just use the previous elevation value (from the previous BS line).?ÿPerhaps it makes it easier if as in the example above you have many IFS's.?ÿ?ÿ?ÿ?ÿ

Thanks for the responses. I'll continue to fill it out in the field (I have to anyway :-)).?ÿHave included a copy of my field notes; I did add the HI's before turning it in to the instructor.

I always fill the HI column.

Part of level note keeping.

Just do it. ?ÿA day will come when something is going wrong and you will suddenly understand why it can be very important.

If you're going to keep level notes in a field book, I agree that calculating the HI is just good practice.?ÿ But I no longer keep level notes by hand, I let the digital level do that.

If you don't have Excel in the field it is more convenient to do sums or differences of two numbers at a time.?ÿ If you don't record HI you have to deal with three in each calculation.

FWIW,

I assume that the format of leveling notes was prescribed by your instructor. I do not find the format clear and readily followed. As others note, handwritten notes are no longer the standard being replaced by digital records. Nonetheless notes should be designed to allow others to decipher what took place.

Being old and set in my ways, my preference for handwritten notes would be to have separate lines for the backlight and HI and the foresight and determined height. I even put a instrument symbol whenever a new backsight is taken. See image (without the instrument symbol).

BTW, how would you indicate an inverted rod in your notes? Does your course cover three-wire leveling??ÿ

Keep your car gassed up, a flash light handy and you girlfriend?ÿ aware of short notice cancellations; because you will be doing last minute "Go Backs" to the field.?ÿ

Calculating HI was useful during the days of construction as with the HI, you can easily set out any grades immediately, but with digital levels, there really isn't a need to keep hand written notes.?ÿ

The attached "Excel"?ÿimage (the one starting with?ÿBM13)?ÿis?ÿthe instructor's?ÿfile that he sent us and wants us to follow. However, in the profile leveling image, which is from the lecture notes (and I think the publisher), the format looks similar to yours. He may be fine if we put (BS and HI), and then (FS and ELEV) together. I get my graded field book back on Thursday and will see what I had done in the past labs. I cannot recall.?ÿ

I don't know what an inverted rod is (I'll look it up), so we haven't discussed it. Three-wire leveling was part of the chapter we had to read in Ghilani's text, but it was not discussed in lecture, nor lab, nor home works. So I think we are skipping that.?ÿ We are moving on to Total Stations and angle measurements this week.

Thank you all again. I read many of the posts on this forum?ÿand am learning from you all.

In the event that the use of an inverted rod in leveling is not included in your text, I provide the following example.

If I only have a level and am tasked to determine the height of a short light pole, I determine a height of instrument then have the rodperson hold the rod upside down placing the base of the rod at the top of the short light pole. In this case the foresight is added rather than subtracted.

Hope this is clear.

Cheers,

DMM?ÿ

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