Installation and configuration

Installing the different packages

From the web pages of the different project you will find instructions on how to install them. Here we will cover the configuration part of the process, so that the packages work together. These documentation pages focus on the usage of mpop for processing of satellite data. So as a minimum this package should be installed. mpop uses plugins for reading of satellite data. In order to read the MSG SEVERI data used in many of the document examples the mipp package should be installed. In order to resample image data with mpop the package pyresample must be installed.

Configuration

Environment variables

Environment variables which are needed for pytroll packages are the PYTHONPATH of course, and the PPP_CONFIG_DIR, which is the directory where the configuration files are to be found. If the latter is not defined, the etc directory of the mpop installation is used.

Input data directories

The input data directories are setup in the satellite configuration files, which can be found in the PPP_CONFIG_DIR directory (some template files are provided with mpop in the etc directory):

[seviri-level1]
format = 'xrit/MSG'
dir='/data/geo_in'
filename='H-000-MSG?__-MSG?________-%(channel)s-%(segment)s-%Y%m%d%H%M-__'
filename_pro='H-000-MSG?__-MSG?________-_________-%(segment)s-%Y%m%d%H%M-__'
filename_epi='H-000-MSG?__-MSG?________-_________-%(segment)s-%Y%m%d%H%M-__'


[seviri-level2]
format='mipp'

The different levels indicate different steps of the reading. The level2 section gives at the mpop plugin to read the data with. In some cases, the data is first read from another level, as is this case with HRIT/LRIT data when we use mipp, there we use the level1 section.

The data location is generally dealt in two parts: the directory and the filename. There can also be additional filenames depending on the reader plugin: here, mipp needs also the filename for prologue and epilogue files.

Note that the section starts with the name of the instrument. This is important in the case where several instruments are available for the same satellite. Note also that the filename can contain wildcards (* and ?). It is up to the input plugin to handle these constructs if needed.

Some words on VIIRS configuration

The configuration for reading Suomi-NPP data is provided in the template file Suomi-NPP.cfg.template included in mpop, just as in the case of MSG discussed above and like many other satellites. So far mpop only reads VIIRS, but feel free to write your own reader for ATMS or CrIS. For VIIRS SDR data the configuration may look like this:

[satellite]
instruments = ('viirs',)


[viirs-level2]
filename = SV???_%(satellite)s_d*b%(orbit)s_c*.h5
geo_filenames = G????_%(satellite)s_d*b%(orbit)s_c*.h5
dir = /data/viirs/sdr
geo_dir = /data/viirs/sdr
format = viirs_sdr.ViirsSDRReader

Different from the SEVIRI example above here we see a geo_filenames entry and a geo_dir entry. This is not mandatory, however, as will be clear from the following.

For VIIRS data, where there (except for the DNB) are two possible and different types of geolocation information (terrain corrected and geoid) and where each band-type (I- and M-bands and the DNB) has its own geolocation it is common to have the geolocation data in separate files, separate from the band-data. Thus, the configuration file allows you to specify the naming of these files.

If the parameter geo_filenames is not set the geolocation file pointed to by the value of N_GEO_Ref given in the SDR file will be used.

You can of course keep your archive of VIIRS SDR scenes in separate sub-directories, so that each scene or pass has its own directory. This might e.g. look like this:

[viirs-level2]
filename = SV???_%(satellite)s_d????????_t???????_e???????_b%(orbit)s_*cspp_dev.h5
dir = /data/viirs/sdr/%(satellite)s_%Y%m%d_*_%(orbit)s
format = viirs_sdr.ViirsSDRReader

As you can see here we use the geolocation file specified in the header of the SDR band data files.