[gradsusr] [EXTERNAL] Re: Is there an easy way in GrADS to sample / aggregate a large data set instead of plotting it at full resolution?

[Robert Kuligowski]

All,

     Thanks for your responses!  I couldn't get skip() to work properly 
(it left gaps in the images) but lterp() worked great and I was able to 
cut the rendering time by about 85% by plotting at 1/4 the original 
resolution!

Cheers,

Bob

On 12/15/2020 12:56 PM, Adams, Jennifer M. (GSFC-610.2)[ADNET SYSTEMS 
INC] wrote:
>
> Jeff wrote:
>
> />>You can write a control file and adjust the nx and ny values in the 
> XDEF and YDEF lines /
>
> />> so that GrADS attempts to plot your fields on a coarser grid. /
>
> This will only work if the grid is not rectilinear and you are using 
> PDEF, where the XDEF/YDEF entries describe the destination grid for 
> the pdef interpolation. Otherwise, the XDEF and YDEF entries must 
> match the native grid.
>
> The lterp() and skip() functions will work, but I suggest using 
> ‘define’ to copy the original grid into memory first. This will mean 
> you do the file I/O only once, and will speed up any function you 
> apply to the original grid.
>
> --Jennifer
>
> On Tue, Dec 15, 2020 at 7:36 AM Robert Kuligowski 
> <bob.kuligowski at noaa.gov <mailto:bob.kuligowski at noaa.gov>> wrote:
>
>     All,
>
>          I have some netCDF files with 6501 lines and 18,000 columns that
>     I'm plotting in GrADS, and creating the .png  output files is
>     taking a
>     long time.  I clearly don't need that much detail in the actual
>     image,
>     so is there a simple way to sample or aggregate the data in GrADS
>     before
>     plotting in order to make it render more quickly?  I looked
>     through the
>     documentation but wasn't able to find the droids I'm looking for. 
>     Thanks!
>
>     Cheers,
>
>     -- 
>     Bob Kuligowski, Ph.D.
>     Meteorologist
>     NOAA/NESDIS/Center for Satellite Applications and Research (STAR)
>
>     Mailing Address:
>     National Oceanic and Atmospheric Administration
>     NESDIS STAR/SMCD
>     Bob Kuligowski
>     NCWCP E/RA2
>     5830 University Research Court
>     2nd Floor, Office #2828
>     College Park, MD 20740-3818
>
>     Phone:  (301) 683-3593
>     Fax  :  (301) 683-3616
>
>     http://www.star.nesdis.noaa.gov/star/Kuligowski_B.php
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>
>
> -- 
>
> Jeff Duda, Research Scientist
>
> University of Colorado Boulder
>
> Cooperative Institute for Research in Environmental Sciences
>
> NOAA/OAR/ESRL/Global Systems Laboratory
> Boulder, CO
>
>
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-- 
Bob Kuligowski, Ph.D.
Meteorologist
NOAA/NESDIS/Center for Satellite Applications and Research (STAR)

Mailing Address:
National Oceanic and Atmospheric Administration
NESDIS STAR/SMCD
Bob Kuligowski
NCWCP E/RA2
5830 University Research Court
2nd Floor, Office #2828
College Park, MD 20740-3818

Phone:  (301) 683-3593
Fax  :  (301) 683-3616

http://www.star.nesdis.noaa.gov/star/Kuligowski_B.php
http://www.star.nesdis.noaa.gov/smcd/emb/ff/index.php

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