[Talk-GB] Measuring building height

Warin 61sundowner at gmail.com
Tue Mar 19 22:14:52 UTC 2019


On 20/03/19 07:51, Neil Matthews wrote:
>
> So, I just tried this and I think it has a reasonable chance of giving 
> a reasonable result.
>
> Take a photo of a car outside the building. Measure number of pixels 
> for the car and number of pixels for the building and the height can 
> be approximated by:
>
>     building_pixels / car_pixels * car_height_in_m
>
> I reckon an average of 1.5m might be reasonable for the car height -- 
> otherwise use something more detailed: 
> https://www.automobiledimension.com/ford-car-dimensions.html
>
>
> Obviously, the further the car is from the building the less accurate 
> the measurement will be.
>

The further the camera/photo is from the building the better too. Less 
camera distortion.
>
>
> Cheers,
>
> Neil
>
>
> On 19/03/2019 16:23, Tony Shield wrote:
>>
>> Hi
>>
>> Been figuring out how to do this for a while - my solution-
>>
>> rule - I used 30cm (aka 1 foot), calculator, known length of arm - in 
>> my case .6m, OSM map to measure distance from target.
>>
>> With hand holding rule vertically measure the target height against 
>> the rule for rule height, this is the key measurement, note the 
>> measurement point. From the map measure the distance from the 
>> measuring point to the target
>>
>> With this information and using proportions (which is what a tangent 
>> is) -
>>
>> target height = (rule height in metres * distance from measuring 
>> point to target) / length of arm in metres.
>>
>> Using this technique I have this morning measured known height of of 
>> a local landmark, and the unknown height of a building. The known 
>> height of 50m measured 8cm at a range of 375m. The unknown height of 
>> the building with 5 floors was calculated to be 20.7 metres which 
>> would on the face of it be realistic (from 3cm and 414m). (Botany Bay 
>> mill in Chorley).
>>
>> TonyS999
>>
>>




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