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[python #EFZ-818363]: Metpy Mondays 48 & 49 Satellite Data with CLASS

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  • Subject: [python #EFZ-818363]: Metpy Mondays 48 & 49 Satellite Data with CLASS
  • Date: Tue, 23 Jul 2024 16:05:50 -0600
Greetings!

Apologies for the delayed response.

I'm not sure why this wasn't a problem in the original video, but the problem 
is occurring bevause the 179.99998, 2.982 lon/lat point is outside the domain 
for the Geostationary projection with its default central longitude of 0. An 
easy work-around is to set the central longitude to -100:

    map_crs = ccrs.Geostationary(central_longitude=-100)

Hope this helps!

Ryan

> Hi there,
> I normally make maps from GOES imagery in netcdf format, getting them from
> AWS directly.
> 
> Recently I wanted to plot a GOES-11 CH4 satellite data from october 2011,
> so I downloaded it from CLASS.
> 
> I saw that some MetPy Mondays were about CLASS data so I went through it
> and getting through the part o MetPy Mondays #48 near time 1min40s to
> 6min07s I get a NaN value for the latitude point 1, and there after
> obviously it does not work.Tried also the #49 that uses IR data to see if
> there would be a difference.
> 
> Here is the part of the code where things go wrong:
> --------------------------------------------------------------------------
> # define coordinate reference system
> map_crs = ccrs.Geostationary()
> # find indexes from lat lon coordinates with numpy unravel
> ilon_min = np.unravel_index(np.argmin(lon), lon.shape)
> ilon_max = np.unravel_index(np.argmax(lon), lon.shape)
> #
> ilat_min = np.unravel_index(np.argmin(lat), lat.shape)
> ilat_max = np.unravel_index(np.argmax(lat), lat.shape)
> # minimum and maximum longitude value
> Lon_point_0 = map_crs.transform_point(lon[ilon_min], lat[ilon_min],
> ccrs.Geodetic())[0]
> Lon_point_1 = map_crs.transform_point(lon[ilon_max], lat[ilon_max],
> ccrs.Geodetic())[0]
> # minimum and maximum latitude value
> Lat_point_0 = map_crs.transform_point(lon[ilat_min], lat[ilat_min],
> ccrs.Geodetic())[1]
> Lat_point_1 = map_crs.transform_point(lon[ilat_max], lat[ilat_max],
> ccrs.Geodetic())[1]
> ----------------------------------------------------------
> So the Lat_point_1 gives me NaN, and I cannot figure out why.
> 
> Any suggestions
> 
> goes11.2011.285.053015.BAND_04.nc
> <https://drive.google.com/file/d/1NVcqjpG-3pIxGDMLmiuy58jx2ZnVqLyR/view?usp=drive_web>
> ?


Ticket Details
===================
Ticket ID: EFZ-818363
Department: Support Python
Priority: Low
Status: Closed
===================
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