[ncl-talk] Contour plot with rotated grid shifted to the west
Guido Cioni
guidocioni at gmail.com
Mon Nov 30 11:45:36 MST 2015
Sure, here it is. I think that the problem is that ncl is expecting 2-D
latitudes and longitudes while I have 1-D rlon and rlat..
Yes I tried commenting the centers.
m300382 at mlogin103% ncl_filedump complete.nc
Copyright (C) 1995-2015 - All Rights Reserved
University Corporation for Atmospheric Research
NCAR Command Language Version 6.3.0
The use of this software is governed by a License Agreement.
See http://www.ncl.ucar.edu/ for more details.
Variable: f
Type: file
filename: complete
path: complete.nc
file global attributes:
CDI : Climate Data Interface version 1.4.7 (
http://code.zmaw.de/projects/cdi)
Conventions : CF-1.0
history : Fri Nov 27 13:33:35 2015: cdo -f nc copy
2014011700_000.grib2 2014011700_001.grib2 2014011700_002.grib2
2014011700_003.grib2 2014011700_004.grib2 2014011700_005.grib2
2014011700_006.grib2 2014011700_007.grib2 2014011700_008.grib2
2014011700_009.grib2 2014011700_010.grib2 2014011700_011.grib2
2014011700_012.grib2 2014011700_013.grib2 2014011700_014.grib2
2014011700_015.grib2 2014011700_016.grib2 2014011700_017.grib2
2014011700_018.grib2 2014011700_019.grib2 2014011700_020.grib2
2014011700_021.grib2 2014011700_022.grib2 2014011700_023.grib2
2014011700_024.grib2 2014011700_025.grib2 2014011700_026.grib2
2014011700_027.grib2 2014011700_028.grib2 2014011700_029.grib2
2014011700_030.grib2 2014011700_031.grib2 2014011700_032.grib2
2014011700_033.grib2 2014011700_034.grib2 2014011700_035.grib2
2014011700_036.grib2 2014011700_037.grib2 2014011700_038.grib2
2014011700_039.grib2 2014011700_040.grib2 2014011700_041.grib2
2014011700_042.grib2 2014011700_043.grib2 2014011700_044.grib2
2014011700_045.grib2 2014011700_046.grib2 2014011700_047.grib2
CDO : Climate Data Operators version 1.4.7 (
http://code.zmaw.de/projects/cdo)
dimensions:
ncl_scalar = 1
rlon = 706
rlat = 434
lev = 20
time = 73 // unlimited
variables:
double rlon ( rlon )
long_name : longitude in rotated pole grid
units : degrees
standard_name : grid_longitude
axis : X
double rlat ( rlat )
long_name : latitude in rotated pole grid
units : degrees
standard_name : grid_latitude
axis : Y
character rotated_pole ( ncl_scalar )
grid_mapping_name : rotated_latitude_longitude
grid_north_pole_latitude : 44.999996
grid_north_pole_longitude : 144
double lev ( lev )
long_name : pressure
units : Pa
axis : Z
double time ( time )
units : hours since 2014-01-17 00:00:00
calendar : proleptic_gregorian
float gh ( time, lev, rlat, rlon )
long_name : Geopotential Height
units : gpm
code : 5
grid_mapping : rotated_pole
float t ( time, lev, rlat, rlon )
long_name : Temperature
units : K
grid_mapping : rotated_pole
float u ( time, lev, rlat, rlon )
long_name : U velocity
units : m s**-1
code : 2
grid_mapping : rotated_pole
float v ( time, lev, rlat, rlon )
long_name : V velocity
units : m s**-1
code : 3
grid_mapping : rotated_pole
float w ( time, lev, rlat, rlon )
long_name : Vertical velocity
units : Pa s**-1
code : 8
grid_mapping : rotated_pole
float pv ( time, lev, rlat, rlon )
long_name : Potential vorticity
units : K m**2 kg**-1 s**-1
code : 14
grid_mapping : rotated_pole
float mterh ( time, rlat, rlon )
long_name : Model terrain height
units : m
code : 7
grid_mapping : rotated_pole
Il 30 nov 2015 6:28 PM, "Mary Haley" <haley at ucar.edu> ha scritto:
> Guido,
>
> I'm hoping Dave will weigh in here, but it would help if we could at least
> see the output from:
>
> ncl_filedump pv.nc
>
> Sometimes the global attributes of the file will give some valuable
> information about the correct map projection parameters.
>
> Did you actually try commenting out the mpCenterLatF and mpCenterLonF
> settings? In the script you included, these two resources are still being
> set.
>
> It's possible that the data has already been rotated for you.
>
> --Mary
>
>
>
>
> On Mon, Nov 30, 2015 at 1:33 AM, Guido Cioni <guidocioni at gmail.com> wrote:
>
>> Hi all,
>> I’m trying to produce a contour plot with data on a rotated grid. The
>> original data look like that
>>
>>
>> Since I have the rotated north pole latitude (*44.999996*) and longitude
>> (*144.0*) in my data file I used the second example of the support page
>> on rotated grid.
>>
>> Res1 at tfDoNDCOverlay=True
>> Res1 at mpLimitMode = "Corners"
>> Res1 at mpLeftCornerLatF = lat(0)
>> Res1 at mpLeftCornerLonF = lon(0)
>> Res1 at mpRightCornerLatF = lat(nlat-1)
>> Res1 at mpRightCornerLonF = lon(nlon-1)
>> Res1 at mpCenterLatF = 90 - north_pole_lat
>> Res1 at mpCenterLonF = 180 + north_pole_lon
>>
>> However I get this result ( I believe this is Australia):
>>
>>
>> After several attempts I was able to plot the data using as bounds the
>> “real” coordinates of the rotated projection, without specifying the
>> center, e.g. :
>>
>> Res1 at tfDoNDCOverlay=True
>> Res1 at mpLimitMode = "Corners"
>> Res1 at mpLeftCornerLatF = 30.35458
>> Res1 at mpLeftCornerLonF = -75.14440
>> Res1 at mpRightCornerLatF = 65.1125
>> Res1 at mpRightCornerLonF = 13.87071
>>
>> But the contour plot is still slightly shifted to the west as you can see
>> in this image:
>>
>>
>> I know that in the data file my coordinates span from rlon={340,392.875}
>> and rlat={-9.962499,22.512501}.
>>
>> What am I missing?
>> Is there any additional documentation on rotated grid?
>>
>> Attached is my NCL script (data are too big).
>>
>>
>>
>> Guido Cioni
>> http://guidocioni.altervista.org
>>
>>
>>
>>
>>
>> _______________________________________________
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>>
>
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