[ncl-talk] How to convert a contour map to a raster file from a nc file?

[Dave Allured - NOAA Affiliate]

According to this article, your original Netcdf file is already in a GIS
raster format.

    https://en.wikipedia.org/wiki/GIS_file_formats

You should be able to skip the plotting step, and use the Netcdf file
directly in ArcGIS.  Minor adjustments may be needed for coordinates and
area subsetting.  My guess is that this is really what you want to do.

The expression "raster format" is problematical because it is used for at
least three fundamentally different things in computer graphics.
Generically, this refers to common "bit-mapped" image file formats such as
png, gif, and jpeg.  In GIS and satellite imagery, it refers to a variety
of gridded data formats, including Netcdf.  And NCL has a specialized
usage, referring to the rendering of gridded data as visibly rectangular
blocks when making plots, rather than smooth or segmented outlines.  It
would be nice if these nuances of terminology were discussed in NCL
documentation, but, um, they are not.

To make things more confusing, some of these formats can be "rendered" in
one of the other formats, often losing software compatibility in the
process.  The picture on your example raster_4.ncl is a perfect example of
this.  That is an NCL "raster plot" projected onto a PNG "raster format"
image file for website display.  The "pixels" before and after are
completely different.  So be careful about which usage you are discussing.


On Tue, Jun 9, 2020 at 10:06 AM zoe jacobs via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Dear all NCL users,
>
> I would like to create a map plot in raster format from a nc file . So I
> can then use it on ArcGIS. Please have a look at the following link
> https://www.ncl.ucar.edu/Applications/raster.shtml , example easter_4.ncl .
> I already could plot a contour map from my nc file, and I just wonder which
> command should I add to my script to convert my plot to be in a raster
> format?
> Would you please kindly advise me in this regard?
> Best wishes,
>
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