pyresample.utils package

Submodules

pyresample.utils.cartopy module

pyresample.utils.cf module

Load an AreaDefinition object from a netCDF/CF file.

pyresample.utils.cf.load_cf_area(nc_file, variable=None, y=None, x=None)

Load an AreaDefinition object from a netCDF/CF file.

Parameters:
  • nc_file (string or object) – path to a netCDF/CF file, or opened xarray.Dataset object
  • variable (string, optional) – name of the variable to load the AreaDefinition from. If the variable is not a CF grid_mapping container variable, it should be a variable having a :grid_mapping attribute. If variable is None the file will be searched for valid CF area definitions
  • y (string, optional) – name of the variable to use as ‘y’ axis of the CF area definition If y is None an appropriate ‘y’ axis will be deduced from the CF file
  • x (string, optional) – name of the variable to use as ‘x’ axis of the CF area definition If x is None an appropriate ‘x’ axis will be deduced from the CF file
Returns:

are_def, cf_info – cf_info holds info about how the AreaDefinition was defined in the CF file.

Return type:

geometry.AreaDefinition object, dict

pyresample.utils.proj4 module

class pyresample.utils.proj4.DaskFriendlyTransformer(src_crs, dst_crs, **kwargs)

Bases: object

Wrapper around the pyproj Transformer class that uses dask.

classmethod from_crs(crs_from, crs_to, **kwargs)

Create transformer object from two CRS objects.

transform(x, y, **kwargs)

Transform coordinates.

pyresample.utils.proj4.convert_proj_floats(proj_pairs)

Convert PROJ.4 parameters to floats if possible.

pyresample.utils.proj4.get_geostationary_height(geos_area_crs)
pyresample.utils.proj4.proj4_dict_to_str(proj4_dict, sort=False)

Convert a dictionary of PROJ.4 parameters to a valid PROJ.4 string.

pyresample.utils.proj4.proj4_radius_parameters(proj4_dict)

Calculate ‘a’ and ‘b’ radius parameters.

Parameters:proj4_dict (str or dict) – PROJ.4 parameters
Returns:equatorial and polar radius
Return type:a (float), b (float)
pyresample.utils.proj4.proj4_str_to_dict(proj4_str)

Convert PROJ.4 compatible string definition to dict.

EPSG codes should be provided as “EPSG:XXXX” where “XXXX” is the EPSG number code. It can also be provided as "+init=EPSG:XXXX" as long as the underlying PROJ library supports it (deprecated in PROJ 6.0+).

Note: Key only parameters will be assigned a value of True.

pyresample.utils.rasterio module

pyresample.utils.rasterio.get_area_def_from_raster(source, area_id=None, name=None, proj_id=None, proj_dict=None)

Construct AreaDefinition object from raster.

Parameters:
  • source (str, Dataset, DatasetReader or DatasetWriter) – A file name. Also it can be osgeo.gdal.Dataset, rasterio.io.DatasetReader or rasterio.io.DatasetWriter
  • area_id (str, optional) – ID of area
  • name (str, optional) – Name of area
  • proj_id (str, optional) – ID of projection
  • proj_dict (dict, optional) – PROJ.4 parameters
Returns:

area_def – AreaDefinition object

Return type:

object

Module contents

Miscellaneous utility functions for pyresample.

pyresample.utils.check_and_wrap(lons, lats)

Wrap longitude to [-180:+180[ and check latitude for validity.

Parameters:
  • lons (ndarray) – Longitude degrees
  • lats (ndarray) – Latitude degrees
Returns:

Longitude degrees in the range [-180:180[ and the original

latitude array

Return type:

lons, lats

Raises:

ValueError – If latitude array is not between -90 and 90

pyresample.utils.check_slice_orientation(sli)

Check that the slice is slicing the right way.

pyresample.utils.convert_def_to_yaml(*args, **kwargs)

Convert an area definition to yaml representation.

pyresample.utils.create_area_def(*args, **kwargs)

Create an area definition.

pyresample.utils.fwhm2sigma(fwhm)

Calculate sigma for gauss function from FWHM (3 dB level).

Parameters:fwhm (float) – FWHM of gauss function (3 dB level of beam footprint)
Returns:sigma – sigma for use in resampling gauss function
Return type:float
pyresample.utils.generate_nearest_neighbour_linesample_arrays(source_area_def, target_area_def, radius_of_influence, nprocs=1)

Generate linesample arrays for nearest neighbour grid resampling.

Parameters:
  • source_area_def (object) – Source area definition as geometry definition object
  • target_area_def (object) – Target area definition as geometry definition object
  • radius_of_influence (float) – Cut off distance in meters
  • nprocs (int, optional) – Number of processor cores to be used
Returns:

(row_indices, col_indices)

Return type:

tuple of numpy arrays

pyresample.utils.generate_quick_linesample_arrays(source_area_def, target_area_def, nprocs=1)

Generate linesample arrays for quick grid resampling.

Parameters:
  • source_area_def (object) – Source area definition as geometry definition object
  • target_area_def (object) – Target area definition as geometry definition object
  • nprocs (int, optional) – Number of processor cores to be used
Returns:

(row_indices, col_indices)

Return type:

tuple of numpy arrays

pyresample.utils.get_area_def(*args, **kwargs)

Get an area definition.

pyresample.utils.load_area(*args, **kwargs)

Load an area.

pyresample.utils.parse_area_file(*args, **kwargs)

Parse an area file.

pyresample.utils.recursive_dict_update(d, u)

Update dictionary recursively.

Copied from:

pyresample.utils.wrap_longitudes(lons)

Wrap longitudes to the [-180:+180[ validity range (preserves dtype).

Parameters:lons (numpy array) – Longitudes in degrees
Returns:lons – Longitudes wrapped into [-180:+180[ validity range
Return type:numpy array