[ncl-talk] Help: How to convert the British National Grid (BNG) into the normal latitude and longitude?

[Dave Allured - NOAA Affiliate]

Xiaofeng Li,

You have BNG coordinates on an even 1-Km grid.  I do not know of any
internal NCL solution.

The best solution is to find published latitude and longitude coordinates
for the BNG 1-Km grid from an official source.  These should be in the form
of 2-D equivalent arrays or tables, lats(x,y) and lons(x,y).  NCL can read
2-D equivalent arrays in many different formats, so the exact format is not
important.  And of course, you can easily take a subset out of a larger
reference grid, or a higher resolution grid.

You will need to find these published coordinates for yourself.  I am not
sure whether the 1-Km coordinates are published, but there is an excellent
chance that they are out there somewhere.  There is also published software
that can generate the coordinates for you, but that is more difficult than
just finding and downloading the 1-km grid coordinates from an official
source.

When you have lats(x,y) and lons(x,y), you can read them into NCL and use
them to geolocate your BNG data grids for plotting and other applications.
HTH.

--Dave


On Wed, Nov 16, 2016 at 7:04 AM, Xiaofeng Li <Xiaofeng.Li at newcastle.ac.uk>
wrote:

> Dear all,
>
>         Is there any function in NCL to covert the British National Grid
> (BNG) to the normal latitude and longitude? see the attach NC data,”
> test.nc".
>         I’ve checked this web http://www.ncl.ucar.edu/Do
> cument/Graphics/contour_grids.shtml, and it seems that the BNG is not
> supported by the NCL plotting.
>         Any information is appreciable.
>
> Regards,
> Xiaofeng Li
>
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