[ncl-talk] Fwd: Random file into polar coordinates

[Keren Rosado]

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Begin forwarded message:

> From: Keren Rosado <keren.rosadova at gmail.com>
> Date: November 7, 2017 at 4:10:01 PM MST
> To: Dennis Shea <shea at ucar.edu>
> Subject: Re: [ncl-talk] Fwd: Random file into polar coordinates
> 
> I have latitude and longitude in cartesian coordinates (example of the text file is above). That is the only information I have. I plotted the data before using gsn_add_polymarker for the domain I want e.g. 15N 20N and 54W-58W. The center of this domain is 16.8N and 56W. What the polymaker function did was if I had an observation at 16N and 53W a black dot was drawn. What I need now is transform that 16N-53W (black dot) into cylindrical coordinates using as center 16.8N and 56W. 
> 
>> On Tue, Nov 7, 2017 at 3:25 PM, Dennis Shea <shea at ucar.edu> wrote:
>> Again you need clarify  even more ...Please look at: 
>> 
>> ---
>> 
>>  http://hyperphysics.phy-astr.gsu.edu/hbase/sphc.html
>> 
>> Upper left:
>> 
>> theta is (90-latitude); co-latitude
>> phi is longitude
>> r is the radius of the earth (assuming a spherical earth)
>> 
>> You have all of this information.
>> 
>> ===
>> http://keisan.casio.com/exec/system/1359534351
>> ===
>> The radius at any latitude:  
>>    http://mathforum.org/library/drmath/view/54158.html
>> 
>> r(latitude) = r*cos(latitude)   ; latitude in radians
>> 
>> 
>> 
>> 
>>> On Tue, Nov 7, 2017 at 1:07 PM, Keren Rosado <keren.rosadova at gmail.com> wrote:
>>> R, theta 
>>> 
>>>> On Tue, Nov 7, 2017 at 12:11 PM, Dennis Shea <shea at ucar.edu> wrote:
>>>> Please clarify your question: 
>>>> 
>>>> re: "polar coordinates"
>>>> 
>>>> (a)  r,theta ?  https://en.wikipedia.org/wiki/Polar_coordinate_system
>>>> (b)  lat,lon ? 
>>>> 
>>>>> On Tue, Nov 7, 2017 at 11:52 AM, Keren Rosado <keren.rosadova at gmail.com> wrote:
>>>>> 
>>>>> Hello, 
>>>>> 
>>>>> I have a file with observations for the entire globe for one hour period. 
>>>>> Here are few lines from my txt (observations) files. The highlighted values are for lat and lon: 
>>>>> 2010/08/28,04:00:00.356732, 11.7047, 133.9177,  4.8,  5
>>>>> 2010/08/28,04:00:00.629722, 36.7353,  52.1856, 26.8,  7
>>>>> 2010/08/28,04:00:00.559602, 36.8155,  52.2482,  3.3,  5
>>>>> 2010/08/28,04:00:00.922721,  4.8667, 105.7474,  8.3,  7
>>>>> 2010/08/28,04:00:00.130999, 22.7165,-105.1758, 24.9,  5
>>>>> 2010/08/28,04:00:00.400279, 11.7329, 133.9220, 16.3,  9
>>>>> 2010/08/28,04:00:01.330873, 21.6459,-105.0242,  7.3,  5
>>>>> 2010/08/28,04:00:01.409443, 28.4564, -90.7360,  9.7,  5
>>>>> 
>>>>> 
>>>>> I plotted these observations using ncl function gsn_add_polymarker for the domain I am interested in lat and lon. 
>>>>> 
>>>>> I will like to now how to transform the lat and lon to polar coordinates for the domain I am interested.
>>>>> 
>>>>> Does anyone have an idea of how to to this?
>>>>> 
>>>>> Thanks! 
>>>>> 
>>>>> 
>>>>> 
>>>>> _______________________________________________
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>>>> 
>>> 
>> 
> 
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