[ncl-talk] Contour map: cnFillMode = "CellFill"

[Rick Brownrigg]

Hi,

Are you plotting observational point data?  What are your lat/lons -- cell
centers?

If I understand the issue correctly, and reading the docs for
sf[XY]CellBounds:

    http://ncl.ucar.edu/Document/Graphics/Resources/sf.shtml#sfXCellBounds

You need to calculate the bounds of the cells yourself. For example, if you
have .25degree cells,
and know cell centers, that calculation is easy to come up with the 4
corner points. Not so easy if you have lat/lons and need cells of a
specific are in meters.

Make sense?
Rick

On Mon, Apr 1, 2019 at 2:47 AM <G.Monte at isac.cnr.it> wrote:

> Dears all,
> I have an issue with a map contouring set on "cell fill" mode. When I run
> the script I get the following message errors:
>
> fatal:ContourPlotDraw: The CellFill method for non-rectangular Mesh data
> requires vertices to be explicitly defined using the sf[XY]CellBounds
> resources
> fatal:ContourPlotDraw: draw error
> fatal:ContourPlotDraw: draw error
> fatal:PlotManagerDraw: error in plot draw
> fatal:_NhlPlotManagerDraw: Draw error
>
> The source ascii file consists of an array with three coloumns:
> 1) the first one is latitude
> 2) the second one is longitude
> 3) the third one represents the punctual value I want to plot
>
>
> If I turn in "cnFillMode=AreaFill" it works, but the bounds of the cells
> are not kept by the contouring. I'm pretty sure that the problem will be
> over if I set sf[XY]CellBounds properly, but I really don't know how to
> do.
>
> I only succeeded in plotting my data as a panel plot, which is here
> attached for a rapid visualization. Moreover, I ask you if I could overlay
> these nine plots into a single map and solve my issue.
>
> Thanks in advance,
> Giulio Monte
>
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