[python #FTV-652122]: (No Subject)

Hi,

You can't use MetPy to import ucar.unidata.geoloc; MetPy is Python-based and 
geoloc (netCDF-java) is java-based. Those two do not play well together for the 
most part.

You *can* use MetPy together with xarray to plot/geolocate GOES ABI imagery, 
however:

import matplotlib.pyplot as plt
import metpy
from siphon.catalog import TDSCatalog

# Read data from THREDDS
cat = 
TDSCatalog('https://thredds.ucar.edu/thredds/catalog/satellite/goes/east/grb/ABI/CONUS/Channel05/current/catalog.xml')
nc = cat.datasets[0].remote_access(use_xarray=True)

# Parse the netCDF CF metadata
rad = nc.metpy.parse_cf('Rad')

# Make a plot using matplotlib and CartoPy
fig = plt.figure(figsize=(25, 15), dpi=100)
ax = plt.axes(projection=rad.metpy.cartopy_crs)
extent = (rad.x[0], rad.x[-1], rad.y[0], rad.y[-1])
ax.imshow(rad, extent=extent, cmap='Greys_r')
ax.coastlines(color='yellow', linewidth=0.5, resolution='10m')
ax.set_extent((-113, -62, 15.25, 50.75))

If you're not interested in plotting, but just getting the projection 
information out of the file, you can just use xarray and pyproj:

import matplotlib.pyplot as plt
import numpy as np
from pyproj import Proj
from siphon.catalog import TDSCatalog

# Read data from THREDDS
cat = 
TDSCatalog('https://thredds.ucar.edu/thredds/catalog/satellite/goes/east/grb/ABI/CONUS/Channel05/current/catalog.xml')
nc = cat.datasets[0].remote_access(use_xarray=True)

# Set up the PyProj projection based on metadata
h = proj_info['perspective_point_height']
geo_proj = Proj(proj='geos',
                lon_0 = proj_info['longitude_of_projection_origin'],
                lat_0 = proj_info['latitude_of_projection_origin'],
                h=h,
                a=proj_info['semi_major_axis'],
                b=proj_info['semi_minor_axis'],
                sweep=proj_info['sweep_angle_axis'],
                units='m')

# Convert 1D x, y arrays to 2D arrays. Need to scale by height to
# convert radians to meters as expected by projection
x, y = np.meshgrid(nc.Rad.x.values * h, nc.Rad.y.values * h)

# Get lat/lon values from x/y
lon, lat = geo_proj(x, y, inverse=True)

Hope this helps,

Ryan

> Dear Staff
> i wonder if I can use https://www.unidata.ucar.edu/software/metpy/
> to import ucar.unidata.geoloc
> <https://www.unidata.ucar.edu/software/netcdf-java/v4.3/v4.2/javadoc/ucar/unidata/geoloc/package-summary.html>
> libraries
> otherwise, any suggestions?
> 
> I need to do this in order to geolocate l1b abi images


Ticket Details
===================
Ticket ID: FTV-652122
Department: Support Python
Priority: Low
Status: Closed
===================
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