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. 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 > > On 19/03/2019 09:30, Brian Prangle wrote: >> There are also theodolite apps for smartphones >> >> On Tue, 19 Mar 2019, 00:17 Rob Nickerson, <[email protected] >> <mailto:[email protected]>> wrote: >> >> For building heights why not try using a laser measure? Those >> with a Pythagoras Measurement mode should automate the >> calculations for you. >> >> Price has fallen a lot over the years. Seems like even a basic >> £30 device is sufficient. >> >> Best regards, >> Rob >> _______________________________________________ >> Talk-GB mailing list >> [email protected] <mailto:[email protected]> >> https://lists.openstreetmap.org/listinfo/talk-gb >> >> >> _______________________________________________ >> Talk-GB mailing list >> [email protected] >> https://lists.openstreetmap.org/listinfo/talk-gb > > _______________________________________________ > Talk-GB mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-gb
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