Re: transform a projection into regular lat-lon

Hi Mark,
Since the NCL is looking for the center longitude and you have the north pole, I think you should try setting mpCenterLatF to 39.25 - 90. Let us know if that does not produce a reasonable plot.
 -dave

On Feb 28, 2012, at 6:11 AM, Mark Chan wrote:

> Dear Dennis,
>
> Thanks a lot for your message. I wonder whether I could find the input data for the example in the website, so I could compare it with my data.
> For instance, how could I get the parameters as in the below since my data has something like "grid_north_pole_latitude : 39.25".
> res@mpCenterLonF = lon2d@Longitude_of_southern_pole
> res@mpCenterLatF = lon2d@Latitude_of_southern_pole + 90
> Thanks a lot again!
>
> Mark
> From: Dennis Shea <shea@ucar.edu>
> To: Mark Chan <cym263@yahoo.com>
> Cc: "ncl-talk@ucar.edu" <ncl-talk@ucar.edu>
> Sent: Monday, February 27, 2012 5:39 PM
> Subject: Re: transform a projection into regular lat-lon
>
> Does
> http://www.ncl.ucar.edu/Applications/rotatedltln.shtml
> answer your question. Please read the text.
>
> Good Luck
>
> On 2/27/12 3:31 AM, Mark Chan wrote:
> > Dear NCL users,
> >
> > I have a model output file having info as in the below. I was told it is
> > "rotated projection" (I don't know exactly what it is).
> > Could any one help give me a suggestion how to transform this data into
> > regular lat-lon projection? The main issue is how to define its
> > projection when reading it with NCL?
> >
> > Thanks so much in advance!
> > Mark Chan
> >
> > ----------------------Data file info ------------------------
> > dimensions:
> > ncl_scalar = 1
> > rlat = 92
> > rlon = 108
> > time = 87648 // unlimited
> > height_2m = 1
> > variables:
> > double time ( time )
> > standard_name : time
> > units : seconds since 1989-01-01 00:00:00
> > calendar : standard
> > float rlon ( rlon )
> > standard_name : grid_longitude
> > units : degrees
> > float rlat ( rlat )
> > standard_name : grid_latitude
> > units : degrees
> > float lon ( rlat, rlon )
> > standard_name : longitude
> > units : degrees_east
> > float lat ( rlat, rlon )
> > standard_name : latitude
> > units : degrees_north
> > float height_2m ( height_2m )
> > long_name : height above surface
> > units : m
> > character rotated_pole ( ncl_scalar )
> > long_name : coordinates of the rotated North Pole
> > grid_mapping_name : rotated_latitude_longitude
> > grid_north_pole_latitude : 39.25
> > grid_north_pole_longitude : -162
> > short tas ( time, height_2m, rlat, rlon )
> > standard_name : air_temperature
> > long_name : 2m temperature
> > units : K
> > coordinates : lon lat
> > scale_factor : 0.004940663
> > add_offset : 161.8932
> > ====================================
> >
> > -----------------Its grids info is
> > as-----------------------------------------------------
> > rlon = -10.445, -10.335, -10.225, -10.115, -10.005, -9.895, -9.785, -9.675,
> > -9.565, -9.455, -9.345, -9.235, -9.125, -9.015, -8.905, -8.795, -8.685,
> > -8.575, -8.465, -8.355, -8.245, -8.135, -8.025, -7.915, -7.805, -7.695,
> > -7.585, -7.475, -7.365, -7.255, -7.145, -7.035, -6.925, -6.815, -6.705,
> > -6.595, -6.485, -6.375, -6.265, -6.155, -6.045, -5.935, -5.825, -5.715,
> > -5.605, -5.495, -5.385, -5.275, -5.165, -5.055, -4.945, -4.835, -4.725,
> > -4.615, -4.505, -4.395, -4.285, -4.175, -4.065, -3.955, -3.845, -3.735,
> > -3.625, -3.515, -3.405, -3.295, -3.185, -3.075, -2.965, -2.855, -2.745,
> > -2.635, -2.525, -2.415, -2.305, -2.195, -2.085, -1.975, -1.865, -1.755,
> > -1.645, -1.535, -1.425, -1.315, -1.205, -1.095, -0.985, -0.875, -0.765,
> > -0.655, -0.545, -0.435, -0.325, -0.215, -0.105, 0.005, 0.115, 0.225,
> > 0.335, 0.445, 0.555, 0.665, 0.775, 0.885, 0.995, 1.105, 1.215, 1.325 ;
> >
> > rlat = -8.855, -8.745, -8.635, -8.525, -8.415, -8.305, -8.195, -8.085,
> > -7.975, -7.865, -7.755, -7.645, -7.535, -7.425, -7.315, -7.205, -7.095,
> > -6.985, -6.875, -6.765, -6.655, -6.545, -6.435, -6.325, -6.215, -6.105,
> > -5.995, -5.885, -5.775, -5.665, -5.555, -5.445, -5.335, -5.225, -5.115,
> > -5.005, -4.895, -4.785, -4.675, -4.565, -4.455, -4.345, -4.235, -4.125,
> > -4.015, -3.905, -3.795, -3.685, -3.575, -3.465, -3.355, -3.245, -3.135,
> > -3.025, -2.915, -2.805, -2.695, -2.585, -2.475, -2.365, -2.255, -2.145,
> > -2.035, -1.925, -1.815, -1.705, -1.595, -1.485, -1.375, -1.265, -1.155,
> > -1.045, -0.935, -0.825, -0.715, -0.605, -0.495, -0.385, -0.275, -0.165,
> > -0.055, 0.055, 0.165, 0.275, 0.385, 0.495, 0.605, 0.715, 0.825, 0.935,
> > 1.045, 1.155 ;
> >
> >
> >
> >
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Received on Tue Feb 28 10:18:36 2012