Altitude finder

Not my field, but I know laser range-finders and distance measurers exist. They would be straight line, so altitude can be figured if you know the angles. I have no idea what their distance limitations might be.

Laser range finders can measure any distance, but each model will have its own limitations.

As lbender said, if you know the distance and the angle accurately you can tell the height. Keep in mind that as the distance gets greater the curvature of the Earth will come into play making the math much tougher.

http://www.rfs.org.uk/learning/measuring-trees

Yeah, you can use a number of devices.

http://en.wikipedia.org/wiki/Hypsometer

profen4 said:

But nothing that does it automatically? i.e. point at a building and it tells you the height in relation to sea level. I thought maybe there was some GPS laser gadget that might do it.

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I don't know if such a device exists, but you'd need to know several things:

1. elevation of base of building, relative to sea level. Once that is established, it becomes a Pythagorean trigonometric problem.

2. horizontal distance from building. One leg of the right triangle you need to calculate

3. angle of sight, = angle of hypotenuse of right triangle.

From the latter two measurements, you can calculate the third leg of the triangle, which would equal the height of the building. Add that to the basal elevation above sea level, and you have your answer.

For best accuracy, you also need to take into account your own height, presuming this is some form of hand-held sighting instrument. And I'm also assuming your position is at a horizontal level with the base of the building, which might not be true.

But I was a Boy Scout once, and we did an exercise like this, in a cruder way, to figure out the height of trees. With a little ingenuity, you can actually get pretty good results, and fairly quickly, even without an electronic device.

caw

If it's a fiction you can make it up and have it sound plausible. Just say the device gets a distance using a laser, gets an angle reading from the device and makes a calculation using data plus elevation data from a GPS.

Here you go:
http://www.fltgeosystems.com/disto/leica-disto-d5-lca764553/

Most GPS devices will indicate altitude above sea level FOR THAT DEVICE. It's not a stretch to combine the above mentioned devices with the GPS that will render an gross altitude for the top of the building/object.

profen4 said:

I thought maybe there was some GPS laser gadget that might do it.

Click to expand...

There are. We don't use them hand-held but on a monopod or tripod for accuracy. And they don't come cheap. But surveyors use these all the time.

Trimble is a major manufacturer of this type of equipment: http://www.trimble.com/

Jeff

There are also ultrasonic range finders.