1.5.1.1.7.1.18. polar2grid.readers.modis_l1b module

The MODIS Reader operates on HDF4 Level 1B files from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Aqua and Terra satellites. The reader is designed to work with files created by the IMAPP direct broadcast processing system (file naming conventions such as a1.17006.1855.1000m.hdf), but can support other types of L1B files, including the NASA archived files (file naming conventions such as MOD021KM.A2017004.1732.005.2017023210017.hdf). The reader can be specified to the polar2grid.sh script by using the reader name modis or modis_l1b.

This reader’s default remapping algorithm is ewa for Elliptical Weighted Averaging resampling. The --weight-delta-max parameter set to 10 and the --weight-distance-max parameter set to 1.

It provides the following products:

Product Name	Description
vis01	Visible 1 Band
vis02	Visible 2 Band
vis03	Visible 3 Band
vis04	Visible 4 Band
vis05	Visible 5 Band
vis06	Visible 6 Band
vis07	Visible 7 Band
vis26	Visible 26 Band
bt20	Brightness Temperature Band 20
bt21	Brightness Temperature Band 21
bt22	Brightness Temperature Band 22
bt23	Brightness Temperature Band 23
bt24	Brightness Temperature Band 24
bt25	Brightness Temperature Band 25
bt27	Brightness Temperature Band 27
bt28	Brightness Temperature Band 28
bt29	Brightness Temperature Band 29
bt30	Brightness Temperature Band 30
bt31	Brightness Temperature Band 31
bt32	Brightness Temperature Band 32
bt33	Brightness Temperature Band 33
bt34	Brightness Temperature Band 34
bt35	Brightness Temperature Band 35
bt36	Brightness Temperature Band 36
ir20	Radiance Band 20
ir21	Radiance Band 21
ir22	Radiance Band 22
ir23	Radiance Band 23
ir24	Radiance Band 24
ir25	Radiance Band 25
ir27	Radiance Band 27
ir28	Radiance Band 28
ir29	Radiance Band 29
ir30	Radiance Band 30
ir31	Radiance Band 31
ir32	Radiance Band 32
ir33	Radiance Band 33
ir34	Radiance Band 34
ir35	Radiance Band 35
ir36	Radiance Band 36
fog	Temperature Difference between BT31 and BT20
true_color	Ratio sharpened rayleigh corrected true color
false_color	Ratio sharpened rayleigh corrected false color

For reflectance/visible products a check is done to make sure that at least 10% of the swath is day time. Data is considered day time where solar zenith angle is less than 90 degrees.

class polar2grid.readers.modis_l1b.ReaderProxy(scn: Scene, user_products: list[str])

Bases: ReaderProxyBase

Provide Polar2Grid-specific information about this reader’s products.

property _aliases: dict[str, DataQuery]

get_all_products() → list[str]

Get all polar2grid products that could be loaded.

get_default_products() → list[str]

Get products to load if users hasn’t specified any others.

is_polar2grid_reader: bool = True

polar2grid.readers.modis_l1b.add_reader_argument_groups(parser: ArgumentParser, group: _ArgumentGroup | None = None) → tuple[_ArgumentGroup | None, _ArgumentGroup | None]

Add reader-specific command line arguments to an existing argument parser.

If group is provided then arguments are added to this group. If not, a new group is added to the parser and arguments added to this new group.