OT: Measuring Heights.

[David Sparkes]

I need your help here, both practical and therapeutic, because it's been a rather trying day.

In two areas of my activities, I've found the need to know the heights of structures or trees, say ~8 metres and above, without having the equipment to do it properly, or the experience to do it 'by eye'.

For both the buildings and the trees, accuracy of half a metre in eight metres is probably 'good enough'. I'm not sure 'accurately' is entirely appropriate, but it will do.
Anything taller than ~eight metres the same '0.5 in 8' (6.25%?) can be allowed, or even increased.

I had a brilliant idea, only to be bitterly disappointed when it was put to the test
The idea was to find an 'app' for my Android phone and tablet which would do the measuring for me, using the very sophisticated sensors and software these tools carry inside them.
Searching Google Play Store with the term 'android to measure height of buildings' I reviewed the results and tried 3 results. The first two were paid for (via PayPal), used the built in camera, but when tested were found to be unusable, to any acceptable degree. Having tested them I pressed the Refund button, and received the emails confirming my PayPal account has been refunded. The third was free, but was similarly deleted.

Does anyone else have an app they can recommend for this purpose?

From the 'Smart Tool' set I trialled ' Smart Measure Pro', which was inconsistently incorrect, even after calibration.
'Quick Height' from Vincent Programming. This one didn't use the camera, merely relying on the screen being aligned precisely with the points of measurement. This app did say that 'accuracy was entirely down to the operator', but it was like targetting the apple that William Tell aimed for. His skill was special, I clearly don't have it.
I have forgotten the free one I tried.

Thankyou.

[Bowie69]

Protractor, piece of string, and by eye?

[Arjan]

We use laser measurement equipment for that.

Distance to base, distance to the top, measure the angle and you know the height.

The fancy once have a build in function for that.

We use them also for measuring space under high tension wiring.....

Very useful..

But, not wanting to sound pedantic or so, why the need to measure the height bunt not accurately ?

 

 

Edited February 19, 2017 by Arjan

[reb78]

I was going to suggest similar to above. 

 

One of those spirit levels that doubles as a protractor, tape a cheap laser pointer to it. Measure the distance from the base of object to where you measure the angle to the top (x), you can find the top using your laser pointer taped to the level, then a bit of basic trig. 

[landroversforever]

That was going to be my suggestion Reb, it's then easy to feed those numbers into a trig calculator such as 'Trig Solver' I use on my iPhone. I'm sure it's free too. 

 

[David Sparkes]

Thanks guys, always worthwhile to revisit the basics :-)
Yes, I understand the trigonometry.
Yes, I had also come to the conclusion that a substantial tripod, as used by commercial people everywhere, was used for a reason, and that I probably needed to replicate that functionality before expecting decent results. Pity though, more expense when I had such high hopes of the expensive technology I already had.

I have a cheap laser level bought but unused, I'll dig it out and review it's capability.

" But, not wanting to sound pedantic or so, why the need to measure the height bunt not accurately ? ".
I am working up a counter argument to an architect who thinks he can put in a planning application without bothering to include piffling details such as height, when the site is the highest point in the village, with any building being a dominant feature over a considerable area.
Simply providing a height, when he doesn't, should be enough. Accurate enough to be 'reasonable by an amateur' is OK, and if the fool falls into the trap of quibbling I can go for a head shot by asking why, if it's so important, didn't he provide the accuracy?
Was it incompetence by a trained and qualified professional, or deliberate action to withhold details, done to make his application seem less unreasonable?
There are other 'errors and omissions' on his application, so it's not just a one off mistake.

Thanks again.

[Cynic-al]

Or the Fred Dibnah approach, a bow and arrow with a bit of string attached, fire it to the top of the object, mark the bit of string on the floor then pull it down and measure the string.

[HoSS]

https://gabrielhemery.com/2011/05/15/how-to-calculate-tree-height-using-a-smartphone/

[honitonhobbit]

basic trig works fine - although theses days I use a laser measuring doohikey

[honitonhobbit]

http://lifehacker.com/5875184/is-there-an-easy-way-to-measure-the-height-of-a-tree

 

this is how we used to do it in the olden times

[Green Bob]

Stick a pole in the ground, wait until its shadow is the same height as it is, then measure the shadow of the thing you're trying to measure...