How to measure height?

[Cheezdoodles]

How can i accuratelty measure the height of my neighbours new house? Its blocking my view. I need the measure in meters above sea. GPS is not accurate enough. Could I use a laser or something, aim it at the sealevel and calculate the angle and height?

The house is still being build and I suspect it's to high. However, local maps are not accurate enough, neither is gps. ( atleast not my GPS)

Edit half my post was missing!!

 

[cjo]

How accurate do you need it?

I'm assuming you can get the height above sea level of the ground by using a GPS. As for the height of the house above this point try:

1. Asking the neighbour the height of the house

2. Find any relevant planning permissions documents


3. Stand a known distance from the highest part of the roof. Imagine a line from the ground to the highest point on the house and measure the angle this makes with the horizontal (i.e. use a sextant like device) and use trigonometry to work out the height of the house.

4. Climb on the roof with a GPS.

 

[WhiningKhan]

Do you actually need to do that? Sounds like your issue would require contact to building authority (unless you are planning to apply direct extortion to your neighbours). The authorities should have both the terrain height and building heights in blueprints already. But if you want to check if the real height of the building matches the blueprints, a laser rangefinder and a bit of applied trigonometry should do the trick, I suppose...

 

[Mize]

Find a location at a known height in or on your house. You must then measure two things:

1. The distance to a point on the neighbor's house that is at the same height on your house...you use a level to make sure your pointing horizontal and a laser range-finder (hardware store) to measure the distance.

2. Now you must precisely measure the angle between this horizontal line between your houses and the top of his house directly above the measured horizontal point.

What you have created is a right-triangle with one known side and one known angle.

Since tan(theta) = opposite/adjacent (opposite is the height between the horizontal and the top and adjacent is the horizontal distance). opposite = horizontal*tan(theta).

 

[Blazkowicz]

I was thinking about using the Thales theorem, I remember we were told it was used to mesure the heights of pyramids.

it's working in the same right triangle as in Mize's job, but you have to put a stick up aligned with the ground point and the high point.

here the author has almost computed it. as Fermat would say, I could do it but I'm too lazy to reach for a piece of paper
(uh, I've tried something and end up with A=B^3)

 

[DarthShader]

http://www.brighthub.com/engineering/civil/articles/46276.aspx

 

[Mintmaster]

Do you have any other reference point with known height above sea level? It's hard to measure angles accurately (i.e. tenth of a degree) with respect to the direction of gravity with only homemade equipment, so a reference point would help.

 

[Mize]

You should hurry though...I hear sea levels are rising so that building gets shorter by the decade!

 

[zed]

ring up a surveyer place & speak to someone, Im sure for some under the table cash someone will come out & accurately measure it (a couple of mins), or next time you see one out & about have a chat.

Speaking as someone who tramps, Also GPS is terrible for measuring height! (worse that horizontal stuff) i.e. its gonna be meters off, IIRC perhaps 10or more meters. i.e. u could take a measurement on the roof & then take one on the ground & read that the ground is higher!

 

[Davros]

jump off his roof and time how long it takes to hit the ground

 

[rendezvous]

Can't "Plan- og bygningsetaten" in your "kommune" help you out.
Shouldn't they know how high the house is and at what level the ground is?

 

[3dcgi]

You can probably measure the dimensions fairly easily with PhotoModeler though I'm not sure if the demo is full featured. You just need to snap a few pictures of the house and if you know a couple measurements near the ground you can create a simple model of the house complete with dimensions.
http://www.photomodeler.com/products/default.htm

 

[MfA]

GPS could give you accurate height if you had the right equipment and there are differential GPS transmitters in your area.

The only other way to get accurate sea level height measurement without a reference point is actually being able to see the sea. You could in theory determine your height from the angle (compared to level) to the sea horizon (and of course take into account the tide). Then proceed with the angle/level based measurements already suggested.

All in all I'd have to go with the "hire a surveyor" option ...

 

[eastmen]

Use a match and some gas . Height of the house will be 0 feet (i kid)