[ncl-talk] discrepancy between greenland ncl map and output from CISM

[Mary Haley]

Michele,

When you set:

  res at tfDoNDCOverlay      =   True


then you are effectively telling NCL that you know the *exact* map
projection parameters that the data was measured on, and thus NCL will not
not do any calculations to transform your data to the map parameters that
you've set.

It looks like you have the lat/lon arrays for your data, so as a debugging
test, I suggest plotting your data and force NCL to do the calculations. To
do this, you need to remove this line:

  res at tfDoNDCOverlay      =   True

and set these two lines:

  res at sfXArray              = lon      ; this will force NCL to do the map
projection

  res at sfYArray              = lat

Let ncl-talk know if the plot looks any better.  If you continue to have
problems with this, then can you provide the data file needed by your
script?

Thanks,

--Mary





On Tue, May 15, 2018 at 3:37 AM, Michele Petrini - CITG <
M.Petrini at tudelft.nl> wrote:

> Dear help desk,
>
> I am trying to plot Greenland ice thickness from a CISM simulation.
> Everything works fine - except that it looks that the ice sheet is a little
> bit shifted to the right (see attached figure: the small brown ice patch in
> the North-East should be entirely on land, and that’s the same for other
> bits in the eastern margin).
>
> The projection settings I am using coincides with those used in CISM (I am
> using lon/lat and projection settings as in the input file for my
> simulation), and the resources I set are
>
>   res at mpLimitMode       = "Corners"
>   res at mpLeftCornerLatF      = lat(0,0)
>   res at mpLeftCornerLonF      = lon(0,0)
>   res at mpRightCornerLatF     = lat(ny-1,nx-1)
>   res at mpRightCornerLonF     = lon(ny-1,nx-1)
>   res at trGridType   = "TriangularMesh"
>   res at mpProjection = "Stereographic"  ; Change the map projection.
>   res at mpDataBaseVersion     = "mediumres"
>   res at mpCenterLonF = -45.0
>   res at mpCenterLatF = 70.0
>   res at tfDoNDCOverlay      =   True
>
> Do you know the reason for - and if it is possible to solve - this
> discrepancy? I attach also the contour_movie.ncl file if you want to have a
> look (the figure attached is just one snapshot).
>
> thanks,
> Michele
>
>
>
>
> ******************************************************************
> Michele Petrini
>
> PhD in Earth Science and Fluid Mechanics
> Department of Geoscience and Remote Sensing, TUDelft
> Delft, The Netherlands
>
> M.Petrini at tudelft.nl
> +39 3398367372
> michele.petrins (Skype alias)
>
>
>
>
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