[ncl-talk] Regridding irregularly spaced data onto a regular grid

[Dave Allured - NOAA Affiliate]

Zilore,

Sorry, that example #1 is not set up correctly for your kind of data.  Try
the attached script.  This is another triangular mesh example that does use
need extra coordinate arrays.

If you still want to regrid, then I found that ESMF regridding example
works easily with your sample data.

http://www.ncl.ucar.edu/Applications/ESMF.shtml#ex21

--Dave


On Sat, Jul 26, 2014 at 5:24 PM, Dave Allured - NOAA Affiliate <
dave.allured at noaa.gov> wrote:
>
> Zilore,
>
> Please look at the first example on the Station Data example page:
> http://www.ncl.ucar.edu/Applications/station.shtml
>
> You said that you wanted to plot contours.  This simple example plots
contours WITHOUT first putting data on a regular grid.  It uses a
triangular mesh plotting technique.  For irregular coordinates, this
technique will actually make a more accurate contour map than one made from
a regular grid.
>
> Will this example meet your needs?  My apologies if this was already
discussed previously.
>
> --Dave
>
>
> On Sat, Jul 26, 2014 at 4:40 PM, zilore mumba <zmumba at yahoo.com> wrote:
>>
>> I have x,y,z data on an irregularly spaced geographical grid, which I
want to put on a regular grid to be able to plot contours.
>> My data is below (id, long., lat., rainfall).
>> 01  28.92  -2.47  286.5
>> 02  29.02  -2.68  168.8
>> 03  29.25  -1.67  243.4
>> 04  29.42  -2.07  204.9
>> 05  29.55  -1.58  286.9
>> 06  29.57  -2.48  230.
>> 07  29.6   -1.5   177.5
>> 08  29.72  -2.18  290.
>> 09  30.05  -1.6   206.5
>> 10  30.13  -1.97  178.1
>> 11  30.5   -2.15  156.7
>> My sincere apologies because this is a question I already asked more
than 6 months ago and I still have not found a solution.
>> The question is: Is it possible to do what I want to do in ncl?
>> 1. I have tried 2dgrid.ncl which seems to but am not able to figure out
how to write output to file, and the z values all seem to be above 370
(well above what I have in my file).
>> 2. I have try the Fortran single precision linear interpolation at
Natgrid Examples and run the fortran program with ncargf77 filename I get
the errors below:
>> Advice will be appreciated.
>>
>> ncargf77 natgrid.f
>> gfortran -fPIC -fno-second-underscore -fno-range-check -fopenmp -O
natgrid.f -L/usr/local/lib -L/usr/X11R6/lib64 -lncarg -lncarg_gks -lncarg_c
-lX11 -lXext -lcairo -lfontconfig -lpixman-1 -lfreetype -lexpat -lpng -lz
-liconv -lXrender -lbz2
>> /usr/bin/ld: cannot find -lX11
>> /usr/bin/ld: cannot find -lXext
>> /usr/bin/ld: cannot find -lcairo
>> /usr/bin/ld: cannot find -lfontconfig
>> /usr/bin/ld: cannot find -lpixman-1
>> /usr/bin/ld: cannot find -lfreetype
>> /usr/bin/ld: cannot find -lexpat
>> /usr/bin/ld: cannot find -liconv
>> /usr/bin/ld: cannot find -lXrender
>> /usr/bin/ld: cannot find -lbz2
>> collect2: error: ld returned 1 exit status
>>
>>
>>
>>
>>
>>
>>
>> Natgrid Examples
>> Natgrid examples Overview This module contains source codes for all of
the examples referenced by the other modules in the documentation. Links to
all of the example plots are provided.
>> View on w3.pppl.gov
>> Preview by Yahoo
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