[ncl-talk] gsn_csm_contour_map_ce at high resolution

[David Brown]

Hi Ruben,
There are two things that need to be set correctly to get higher than
default resolution for raster plots.

First, you need to set the resolution of the PNG image (assuming you
are drawing to PNG). This involves setting
wkWidth and wkHeight. Current limitations in NCL mean that there is no
advantage to setting these to different values. The ultimate
resolution will be the smaller of the two values. These resources set
the size in pixels of the plot view space as a whole including
tickmarks, titles and white space around the actual plot. So if the
viewport where the actual plot resides is, for example, 60% of this
space in either direction, you should divide the desired resolution by
0.6 to get a larger number to set for wkWidth/wkHeight.

Second, you need to increase the resolution at which the RasterFill
contour plot is plotted. This is set most directly using the resource
cnRasterCellSizeF. Note that this is the inverse of the resolution
value. So if you want the plot itself to have 6000 x 6000 cells you
would set cnRasterCellSizeF 1 / 6000.0.

Hope this helps.
 -dave

On Tue, Jul 28, 2015 at 12:33 PM, Ruben van Hooidonk <rubski at gmail.com> wrote:
> Hi,
>
> When I try to plot a large map (the Pacific ocean) of high resolution data
> (in this case ~4km), the data gets aggregated in larger pixels.
>
> I've uploaded an image where I've zoomed in on Hawaii to illustrate the
> issue/feature. It is the same data plotted using:
> mpres at mpMinLatF             = 18.
> mpres at mpMaxLatF             =  23.
> mpres at mpMinLonF             = -161.
> mpres at mpMaxLonF             =  -154.
>
> And the image on the left bottom is plotted using:
> mpres at mpMinLatF             = -35.
> mpres at mpMaxLatF             = 35.
> mpres at mpMinLonF             = 98.
> mpres at mpCenterLonF          = 190.
>
> http://i.imgur.com/bTrMg8a.png
>
> I want to know, is there a way that I can plot the data at the actual
> resolution?
>
> I'm using:
>   wks_type at wkAntiAlias="Off"
>   mpres at cnFillMode       = "RasterFill"       ; Raster Mode
>   mpres at mpDataResolution="Finest"
> In both plots.
>
> Thanks for any suggestions.
> Ruben
>
>
> NCL version 6.3.0
> OS X 10.10.4
>
>
>
>
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