[ncl-talk] Missing color fill when using gsn_csm_contour_map (ncl V 6.4.0)

[Dennis Shea]

[0]
If you are just learning NCL, I suggest you look at the *User Manual *at:
      *http://www.ncl.ucar.edu/Document/Manuals/*
<http://www.ncl.ucar.edu/Document/Manuals/>

[1]
As noted by Toni,

u = U(0,,:,:)

is not correct. In fact, it should have generated a *fatal *subscript syntax
error.
Note: although "fatal", NCL will continue. In fact, it will still try to
create the plot. Since it did not have valid data, NCL generated a
background and a default color lable bar. That is what you attached.

[2]
Your following resource setting needs some clarification:

  res at tiMainString    = "NCL version 6.1.x will give you gray land"

For historical reasons, NCL's default graphic mode is black-and-white
(B/W). This is true of *all* NCL versions. Not just 6.1.x.
When, 'gsn_csm_contour_map' is used, the default background is continental
outlines with light gray used to fill land areas. See:

   *http://www.ncl.ucar.edu/Applications/cylineq.shtml*
<http://www.ncl.ucar.edu/Applications/cylineq.shtml>
   Examples 1 and 2

Color is turned on via:
   res at cnFillOn = True     ; make color graphic

When color is activated, (a) the background map including the light gray
land fil is generated; then, (b) the color contour are drawn over that
background.  The light gray land fill is overwritten (no big deal). The
following resource setting tells the 'gsn_csm_contour_map' do the colr
contours and then force the gray land fill last. [There are some reasons
for doing that.]

res at mpFillDrawOrder = "PostDraw" ; Make sure land fill is drawn
                                   ; on top of filled contours

[3]
If you want you can ftp a sample file to:

  ftp ftp.cgd.ucar.edu
  anonymous
  your_email
  cd incoming
  put MAM_GEOS_1anee.cam.h0.2000-12-07-00000.nc
  quit


On Tue, Aug 21, 2018 at 9:45 AM, Toni Klemm <toni-klemm at tamu.edu> wrote:

> Hi Adriana,
>
> I noticed there are two commas in the command to extract the sind vectors:
> u = a->U(0,,:,:)  Could that be the problem?
>
> Could you attach the netCDF file from the example that you’re using? (
> MAM_GEOS_1anee.cam.h0.2000-12-07-00000.nc)
>
> Toni
>
>
>
> *Toni Klemm, Ph.D.*Postdoctoral Research Associate
> Department of Ecosystem Science and Management
> College of Agriculture and Life Sciences
> Texas A&M University, College Station, TX
> Contributor to the Early Career Climate Forum <http://www.eccforum.org>
> www.toni-klemm.de | @toniklemm <http://twitter.com/toniklemm>
>
>
>
>
>
>
>
>
> On Aug 21, 2018, at 10:01 AM, adriana.bossolasco at cnrs-orleans.fr wrote:
>
> Hi all
>
> I have a problem with ncl when I try to plot a contour graphic. I thought
> it was a mistake I was making, but then when I try with a example very
> simple still appears blank. And ncl does not tell me any error.
> Here is the script (have my file but is exactly the same that
> newcolor_1.ncl)
>
> ;************************************************
> ; zonal_2.ncl
> ;
> ; Concepts illustrated:
> ;   - Drawing a zonal means plot
> ;   - Using dim_avg_Wrap to calculate a zonal average
> ;************************************************
> ;load "/usr/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> ;load "/usr/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> ;load "/usr/lib/ncarg/nclscripts/csm/contributed.ncl"
> ;************************************************
> begin
> ;************************************************
> ; variable and file handling
> ;************************************************
> ;---read in zonal winds
>  a = addfile("MAM_GEOS_1anee.cam.h0.2000-12-07-00000.nc","r")
>  u = a->U(0,,:,:)                                ; July zonal winds
>
>  wks  = gsn_open_wks("png","newcolor")  ; send graphics to PNG file
>
>  res                 = True
>  res at gsnMaximize     = True       ; maximize in frame
>  res at cnLinesOn       = False
>  res at cnFillOn        = True
>  res at cnFillPalette   = "BlueYellowRed"   ; change the color palette
>
>  res at mpFillDrawOrder = "PostDraw" ; Make sure land fill is drawn
>                                   ; on top of filled contours
>
>  res at tiMainString    = "NCL version 6.1.x will give you gray land"
>
>  plot = gsn_csm_contour_map(wks,u,res)
> end
>
> I obtained a map without color fill, I was looking in some previous talk
> but nothing works. Can Anyone help me on this? thanks
> I attached the maps
>
> Thank you
> --
> Adriana Bossolasco
> LPC2E UMR 7328 (CNRS, Université d'Orléans)
> 3A avenue de la Recherche Scientifique
> 45071 Orléans Cedex 2 - FRANCE
> Tel  +33 (0)2 38 25 52 85
> e-mail: adriana.bossolasco at cnrs-orleans.fr
> <adriana.bossolasco at cnrs-orleans.fr><newcolor.png>______
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