[ncl-talk] check_for_y_lat_coord: Warning: -Zilore Mumba

[Rick Brownrigg]

Hi Zilore,

Did you see Dennis's reply to this issue from earlier today (Thurs)?  He's
of course correct, and I should have know this, but yes, by NetCDF
definitions, a coordinate variable must be:

i) 1-dimensional
ii) monotonically increasing/decreasing
iii) have the same variable name as its dimension name

So to accommodate curvilinear/2D coordinates, NCL recognizes special
*attributes* names in its plotting routines. So if I comment out these
lines in the script you sent me:

;;;;lat2d    = f->lat             ; (y,x)
;;;lon2d    = f->lon             ; (y,x)
  nt       =1

;;;p!0   = "lat2d" ; No error message at this and following line.
;;;p!1   = "lon2d"

and add:
  p at lat2d = f->lat
  p at lon2d = f->lon

then the errors go away. I've attached the plot I get when I run your
script as is (mask_orig.png) and the one I get when I make the changes
above (mask_mod.png). They are clearly different -- I don't know which one
is right.


With regard to the -inf/inf reporting from printMinMax(), there are some
very extreme values in the "pr" variable. For example, try:

  print(f->pr(2,14,7:33))

and you'll see some extremely large values (compared to the surrounding
context).  These, when multiplied by 86400, as in your code, push the
values beyond the range of floats.

So, I hope that helps, but I'm not certain this even addresses the question
about masking. I have not been able to resolve the issue of yahoo.com
accounts, whether its the ncl-talk mailer, or my email client, or....?   If
you have another email address, perhaps you might register it with
ncl-talk. I know its a pain. But as Dennis states, ncl support strives to
be first rate -- you were not purposefully ignored, nor are your posts
unreasonable!

Rick




On Thu, Apr 25, 2019 at 2:18 PM zilore mumba <zmumba at yahoo.com> wrote:

> Rick, <https://www.ncl.ucar.edu/Applications/Scripts/mask_4.ncl>
> Thank you very much for your prompt reply. I have attached to this mail a
> sample file am working with. Also attached is my modification of mask_4.ncl
> from <https://www.ncl.ucar.edu/Applications/Scripts/mask_4.ncl>
> https://www.ncl.ucar.edu/Applications/Scripts/mask_4.ncl.
> I have commented out the generation of dummy data and made the script to
> read from file. i have also zoomed on a smaller area.
> printMinMax(p,False) shows min = infinity and max=infinity.
> But "cdo infon filename" shows the min, mean and max are ok.
> Plotting simple contours with this data file works.
> My problem is that when I run the script I get the following errors:
> (0)    min=-inf   max=inf
> (0)    check_for_y_lat_coord: Warning: Data either does not contain
> (0)    a valid latitude coordinate array or doesn't contain one at all.
> (0)    A valid latitude coordinate array should have a 'units'
> (0)    attribute equal to one of the following values:
> (0)        'degrees_north' 'degrees-north' 'degree_north' 'degrees north'
> 'degrees_N' 'Degrees_north' 'degree_N' 'degreeN' 'degreesN' 'deg north'
> (0)    check_for_lon_coord: Warning: Data either does not contain
> (0)    a valid longitude coordinate array or doesn't contain one at all.
> (0)    A valid longitude coordinate array should have a 'units'
> (0)    attribute equal to one of the following values:
> (0)        'degrees_east' 'degrees-east' 'degree_east' 'degrees east'
> 'degrees_E' 'Degrees_east' 'degree_E' 'degreeE' 'degreesE' 'deg east'
>
> I hope you can find time to assist.
> Zilore
>
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