[FRIAM] Great Circle

Tom Johnson jtjohnson555 at gmail.com
Mon Sep 20 20:31:20 EDT 2021 

Ed et al. --
Hope you guys saw this interesting story in the NYT Magazine yesterday
about Ingrid Daubechies.  A wonderful character with a great mind.
https://www.nytimes.com/2021/09/14/magazine/ingrid-daubechies.html

TJ

On Mon, Sep 20, 2021 at 6:04 PM Edward Angel <angel at cs.unm.edu> wrote:

> Quaternions avoid much of the ugly trigonometry since quaternion rotation
> is along a great circle. They’re very useful for smooth rotations in
> computer graphics and many aerospace applications.
>
> Ed
> _______________________
>
> Ed Angel
>
> Founding Director, Art, Research, Technology and Science Laboratory
> (ARTS Lab)
> Professor Emeritus of Computer Science, University of New Mexico
>
> 1017 Sierra Pinon
> Santa Fe, NM 87501
> 505-984-0136 (home)   angel at cs.unm.edu
> 505-453-4944 (cell)  http://www.cs.unm.edu/~angel
>
> On Sep 20, 2021, at 9:19 AM, Steve Smith <sasmyth at swcp.com> wrote:
>
> Answering my own earlier question (with props) it seems that a (smooth)
> globe and piece of string would be good support for an intuitive
> approach.    My sister made a "hanging string lampshade" in 3rd grade by
> wrapping cotton string soaked in glue around a large balloon and letting it
> dry.    I inherited it when she went into middle school and was "too cool"
> for it anymore.   I would lay in bed and stare at it, remembering the
> challenges (I helped wrap the string) of getting the slick string to do
> *anything* but following near-great-circles.   The shadows it cast on the
> walls (and furniture) might have been my first awareness of projective
> geometry...  I abandoned it when I went to college.
>
> I assume (REC?) that early age-of-exploration navigators were more
> constrained by trade-winds and convenient resupply/port-of-call than
> great-circles, though misunderstanding spherical geometry would be very
> inconvenient.
>
> I also believe that Polynesian stick charts would have great-circleness
> (or more-to-the-point shortest time paths) built into them by their nature,
> not any arcane understanding of spherical (ellipsoidal) geometry.  I'm sure
> they have been studied quite thoroughly.
>
>
> On 9/19/21 3:36 PM, Stephen Guerin wrote:
>
> In the early 90s, my expat friends in Beijing would often debate which
> were the closer US Cities to Beijing by eyeballing the globe - wish we had
> this too for easy lookup back then. Of course, we could have used lat/longs
> and calculated haversine distances but we had pints to drink - and frankly
> it would have been difficult for me to find the algorithm in the nascent
> web back then ;-)
>
> Beijing (PEK) Great Circle Distances for 10 US cities
> <https://www.greatcirclemap.com/globe?routes=%20PEK-SEA%2C%20PEK-LAX%2C%20PEK-DET%2C%20PEK-SAN%2C%20PEK-MSP%2C%20PEK-YYZ%2C%20PEK-EWR%2C%20PEK-ORD%2C%20PEK-ANC%2C%20PEK-BGR%2C%20PEK-HNL>
>
> <image.png>
>
>
> _______________________________________________________________________
> Stephen.Guerin at Simtable.com <stephen.guerin at simtable.com>
> CEO, Simtable  http://www.simtable.com
> 1600 Lena St #D1, Santa Fe, NM 87505
> office: (505)995-0206 mobile: (505)577-5828
> twitter: @simtable
> z <http://zoom.com/j/5055775828>oom.simtable.com
>
>
> On Sun, Sep 19, 2021 at 3:22 PM Frank Wimberly <wimberly3 at gmail.com>
> wrote:
>
>> That gives a good view, Stephen.  Hawaii is farther south than I
>> thought.  Thanks.
>>
>> ---
>> Frank C. Wimberly
>> 140 Calle Ojo Feliz,
>> Santa Fe, NM 87505
>>
>> 505 670-9918
>> Santa Fe, NM
>>
>> On Sun, Sep 19, 2021, 3:19 PM Stephen Guerin <stephen.guerin at simtable.com>
>> wrote:
>>
>>> I was going to post this similar site but Ed beat me with his :-) This
>>> one also has a globe view...
>>>
>>> https://www.greatcirclemap.com/globe?routes=CLT-HNL
>>> _______________________________________________________________________
>>> Stephen.Guerin at Simtable.com <stephen.guerin at simtable.com>
>>> CEO, Simtable  http://www.simtable.com
>>> 1600 Lena St #D1, Santa Fe, NM 87505
>>> office: (505)995-0206 mobile: (505)577-5828
>>> twitter: @simtable
>>> z <http://zoom.com/j/5055775828>oom.simtable.com
>>>
>>>
>>> On Sun, Sep 19, 2021 at 2:03 PM Frank Wimberly <wimberly3 at gmail.com>
>>> wrote:
>>>
>>>> Thanks, Ed.  That's useful.
>>>>
>>>> ---
>>>> Frank C. Wimberly
>>>> 140 Calle Ojo Feliz,
>>>> Santa Fe, NM 87505
>>>>
>>>> 505 670-9918
>>>> Santa Fe, NM
>>>>
>>>> On Sun, Sep 19, 2021, 1:54 PM Edward Angel <angel at cs.unm.edu> wrote:
>>>>
>>>>> Close: https://www.airmilescalculator.com/distance/clt-to-hnl/
>>>>> _______________________
>>>>>
>>>>> Ed Angel
>>>>>
>>>>> Founding Director, Art, Research, Technology and Science Laboratory
>>>>> (ARTS Lab)
>>>>> Professor Emeritus of Computer Science, University of New Mexico
>>>>>
>>>>> 1017 Sierra Pinon
>>>>> Santa Fe, NM 87501
>>>>> 505-984-0136 (home)   angel at cs.unm.edu
>>>>> 505-453-4944 (cell)  http://www.cs.unm.edu/~angel
>>>>>
>>>>> On Sep 19, 2021, at 1:48 PM, Frank Wimberly <wimberly3 at gmail.com>
>>>>> wrote:
>>>>>
>>>>> Not to change the subject but...
>>>>>
>>>>> A large airliner recently, 15 minutes ago, flew over Santa Fe headed
>>>>> west.  My Flight Radar app tells me that it's a Boeing 777 going from
>>>>> Charlotte to Honolulu at an altitude of 38000 feet.  I wouldn't have
>>>>> thought that Santa Fe was on a great Circle route between those two
>>>>> cities.  But maybe it is.
>>>>>
>>>>> ---
>>>>> Frank C. Wimberly
>>>>> 140 Calle Ojo Feliz,
>>>>> Santa Fe, NM 87505
>>>>>
>>>>> 505 670-9918
>>>>> Santa Fe, NM
>>>>>
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