satpy.readers.utils module
Helper functions for satpy readers.
- satpy.readers.utils.apply_earthsun_distance_correction(reflectance, utc_date=None)[source]
Correct reflectance data to account for changing Earth-Sun distance.
- satpy.readers.utils.apply_rad_correction(data, slope, offset)[source]
Apply GSICS-like correction factors to radiance data.
- satpy.readers.utils.bbox(img)[source]
Find the bounding box around nonzero elements in the given array.
Copied from https://stackoverflow.com/a/31402351/5703449 .
- Returns
rowmin, rowmax, colmin, colmax
- satpy.readers.utils.generic_open(filename, *args, **kwargs)[source]
Context manager for opening either a regular file or a bzip2 file.
Returns a file-like object.
- satpy.readers.utils.get_array_date(scn_data, utc_date=None)[source]
Get start time from a channel data array.
- satpy.readers.utils.get_earth_radius(lon, lat, a, b)[source]
Compute radius of the earth ellipsoid at the given longitude and latitude.
- Parameters
lon – Geodetic longitude (degrees)
lat – Geodetic latitude (degrees)
a – Semi-major axis of the ellipsoid (meters)
b – Semi-minor axis of the ellipsoid (meters)
- Returns
Earth Radius (meters)
- satpy.readers.utils.get_geostationary_angle_extent(geos_area)[source]
Get the max earth (vs space) viewing angles in x and y.
- satpy.readers.utils.get_geostationary_bounding_box(geos_area, nb_points=50)[source]
Get the bbox in lon/lats of the valid pixels inside geos_area.
- Parameters
geos_area – The geostationary area to analyse.
nb_points – Number of points on the polygon
- satpy.readers.utils.get_geostationary_mask(area, chunks=None)[source]
Compute a mask of the earth’s shape as seen by a geostationary satellite.
- Parameters
area (pyresample.geometry.AreaDefinition) – Corresponding area definition
chunks (int or tuple) – Chunk size for the 2D array that is generated.
- Returns
Boolean mask, True inside the earth’s shape, False outside.
- satpy.readers.utils.get_sub_area(area, xslice, yslice)[source]
Apply slices to the area_extent and size of the area.
- satpy.readers.utils.get_user_calibration_factors(band_name, correction_dict)[source]
Retrieve radiance correction factors from user-supplied dict.
- satpy.readers.utils.np2str(value)[source]
Convert an numpy.string_ to str.
- Parameters
value (ndarray) – scalar or 1-element numpy array to convert
- Raises
ValueError – if value is array larger than 1-element or it is not of type numpy.string_ or it is not a numpy array
- satpy.readers.utils.reduce_mda(mda, max_size=100)[source]
Recursively remove arrays with more than max_size elements from the given metadata dictionary.
- satpy.readers.utils.remove_earthsun_distance_correction(reflectance, utc_date=None)[source]
Remove the sun-earth distance correction.
- satpy.readers.utils.unzip_context(filename)[source]
Context manager for decompressing a .bz2 file on the fly.
Uses unzip_file. Removes the uncompressed file on exit of the context manager.
Returns: the filename of the uncompressed file or of the original file if it was not compressed.
- satpy.readers.utils.unzip_file(filename, prefix=None)[source]
Unzip the file ending with ‘bz2’. Initially with pbzip2 if installed or bz2.
- Parameters
filename – The file to unzip.
prefix (str, optional) – If file is one of many segments of data, prefix random filename
number. (for correct sorting. This is normally the segment) –
- Returns
Temporary filename path for decompressed file or None.