class_docstr: Base reader for ABI L1B  L2+ NetCDF4 files.
class_docstr_tok: ["Base","reader","for","ABI","L1B","L2+","NetCDF4","files","."]
docstr: Get the area definition of the data at hand.
docstr_tok: ["Get","the","area","definition","of","the","data","at","hand","."]
code: def _get_areadef_latlon(self, key):
      """Get the area definition of the data at hand."""
      projection = self.nc["goes_lat_lon_projection"]
  
      a = projection.attrs["semi_major_axis"]
      b = projection.attrs["semi_minor_axis"]
      fi = projection.attrs["inverse_flattening"]
      pm = projection.attrs["longitude_of_prime_meridian"]
  
      proj_ext = self.nc["geospatial_lat_lon_extent"]
  
      w_lon = proj_ext.attrs["geospatial_westbound_longitude"]
      e_lon = proj_ext.attrs["geospatial_eastbound_longitude"]
      n_lat = proj_ext.attrs["geospatial_northbound_latitude"]
      s_lat = proj_ext.attrs["geospatial_southbound_latitude"]
  
      lat_0 = proj_ext.attrs["geospatial_lat_center"]
      lon_0 = proj_ext.attrs["geospatial_lon_center"]
  
      area_extent = (w_lon, s_lat, e_lon, n_lat)
      proj_dict = {
          "proj": "latlong",
          "lon_0": float(lon_0),
          "lat_0": float(lat_0),
          "a": float(a),
          "b": float(b),
          "fi": float(fi),
          "pm": float(pm),
      }
  
      ll_area_def = geometry.AreaDefinition(
          self.nc.attrs.get("orbital_slot", "abi_geos"),
          self.nc.attrs.get("spatial_resolution", "ABI file area"),
          "abi_latlon",
          proj_dict,
          self.ncols,
          self.nlines,
          np.asarray(area_extent),
      )
  
      return ll_area_def
  
imports: import logging
  import math
  from contextlib import suppress
  from datetime import datetime
  import dask
  import numpy
  import xarray
  from pyresample import geometry
  from satpy._compat import cached_property
  from satpy.readers import open_file_or_filename
  from satpy.readers.file_handlers import BaseFileHandler
  from satpy.utils import get_dask_chunk_size_in_bytes
label_desc: Use image node_id 11 for calling the NC_ABI_BASE obj's underlying member method code with example usage: obj._get_areadef_latlon(key) and returns: ll_area_def