Author Topic: Estimation of distances?  (Read 4485 times)

DJ_59

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Re: Estimation of distances?
« Reply #15 on: January 25, 2011, 01:15:02 am »

The "tallness" of a mountain definitely is relative to what you see daily.  We love our mountains here in Seattle...



... but visitors from Colorado laugh at us for calling them mountains.  Kind of like we laugh at Californians for calling the brown hills of SoCal mountains.  It's all relative.


Janet Jaguar

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Re: Estimation of distances?
« Reply #16 on: January 25, 2011, 01:40:53 am »
That doesn't look like the Cascades around Mt. Ranier - that's also gorgeous and high, though the peaks around it are much humbler.  Is it the Olympic range?  The years my mother lived there, we never traveled that direction on my vacations.

It's truly beautiful and awesome.

DJ_59

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Re: Estimation of distances?
« Reply #17 on: January 25, 2011, 02:27:06 am »

It is the Olympics.  I love both ranges, but I'm an island fan, so I've spent more time gazing at the Olympics than the Cascades.  The Olympics, once you get across the water, are far more dramatic and vast.  If you're ever this way again, go to Deception Pass and gaze and gaze and gaze.


Janet Jaguar

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Re: Estimation of distances?
« Reply #18 on: January 25, 2011, 02:31:54 am »
That would be a treat.  Truly God-made beauty you have out there.

CHommel

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Re: Estimation of distances?
« Reply #19 on: January 25, 2011, 01:42:42 pm »
Simply gorgeous.  We visited the Pacific Northwest in 2007, and were enthralled by the views of Mt Rainier, peeking out between the buildings in downtown Seattle.  And that was only one mountain.

DJ_59

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Re: Estimation of distances?
« Reply #20 on: January 25, 2011, 03:07:42 pm »

I love it.  Full panorama.  Look west and you've got the Olympics. Turn north and there's Mt. Baker.  To the west, the Cascades, to the south Rainier.  The trade off is tons of rain and the ever-present threat of a massive earthquake.

CHommel

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Re: Estimation of distances?
« Reply #21 on: January 25, 2011, 03:27:44 pm »
How long have you lived there?

I was so tempted to move after our visit, if only to buy fruit every day from Sosio's in Pike's Place market. 

Are you familiar with the street buskers, "Slimpikins"?  We picked up one of their CDs during our visit, and have been on the lookout for another, but alas, they don't sell any through iTunes.

Dean

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Re: Estimation of distances?
« Reply #22 on: September 09, 2012, 12:36:44 am »
There is a 'formula' for figuring distances you can see at sea. 8)   I have it and the examples on my boat. :-[   I'll get it and bring it to here in the next couple days.  (Just tripped over this line of thought today by accident! - Don't worry, no one hurt!) ;D

Janet Jaguar

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Re: Estimation of distances?
« Reply #23 on: September 09, 2012, 02:07:02 am »
I would love it.  The last time I took a stranger around Chicago doing touristy things, she saw our Loop skyline from an 'L' platform (mass transit electric train) and wanted walk instead of ride.  I had to tell her we were a good 5 miles north and 4 miles west, and I wasn't walking 9 miles.

I've never quite understood how you can estimate distance of skyscrapers or planes is you do not already know the size of what you are looking at.

Dean

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Re: Estimation of distances?
« Reply #24 on: September 12, 2012, 04:04:58 pm »
Did some checking.  The formula for horizon distance is  D= 1.17√H  where 'D' is the distance in nautical miles and 'H' is the eye height above sea in feet.  (the '√' is square root - so you need a calculator)

For example if you are 5' tall then the horizon will be visible to 2.61 nautical miles.  If you are on the deck of a ship at 50' then you should be able to see about 8.67 nautical miles.  1.17 √ 50 + 5.

The 'conversion' is use 2.12 for metres to nautical miles.   BTW a Statute mile is 5,280 feet and a nautical mile is 6,076.

There is more about the sight distance when you are looking at something tall like another ship, a light house, etc. I have to research that more. 

Hope this helps. ;D

Janet Jaguar

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Re: Estimation of distances?
« Reply #25 on: September 12, 2012, 06:07:53 pm »
It isn't horizon distance that puzzles me now - our much earlier discussion answered that question completely. 

This goes way back to childhood.  My younger brother tried to look smarter than his big sister (we came out tied in most of those contests :) ) by telling me he could calculate how far above us the airplane flying above us was by the changing angle of flight or some such - I no longer remember what.  I looked at the same plane from our backyard, and asked how did he know it was a big plane flying higher and faster, or a slow plane flying lower and slower?  They'd both travel at the same degrees/minute and might even appear the same size?

I've heard similar things on-and-off since then.  How do you judge distance when you do not know size?