Atmospheric Lidar Package: docs/introduction.rst@ab21bd91bc09 (annotated)

docs/introduction.rst@ab21bd91bc09 (annotated)

docs/introduction.rst

Fri, 02 Nov 2018 16:11:06 +0200

author: Iannis B <ioannis@inoe.ro>
date: Fri, 02 Nov 2018 16:11:06 +0200
changeset 166: ab21bd91bc09
parent 95: efa2d8e1a2e5
permissions: -rw-r--r--

More changes on Diva channels.

 Overview
 ========
 This package provides utilities to handle raw (atmospheric) lidar input data.
 The main format supported are Licel binary files (including the Raymetrics modified format).
 The package provides a single command line tool, called licel2scc that can convert Licel binary files to the
 EARLINET's Single Calculus Chain NetCDF format.
 Installation
 ------------
 The easiest way to install this module is from the python package index using ``pip``::
    pip install atmospheric-lidar
 Using it as a Licel to SCC converter
 ------------------------------------
 Parameter file
 ~~~~~~~~~~~~~~
 Before converting Licel binary to SCC format, you need to create a file linking Licel channels to SCC channels.
 As an example, you can start by changing the file “cf_netcdf_parameters.py” that describe such
 parameters for the Clermont Ferrand  lidar.
 Command line interface
 ~~~~~~~~~~~~~~~~~~~~~~
 The usage of the  ``licel2scc`` program is described below::
     A program to convert Licel binary files to the SCC NetCDF format.
     positional arguments:
       parameter_file        The path to a parameter file linking licel and SCC
                             channels.
       files                 Location of licel files. Use relative path and
                             filename wildcards. (default './*.*')
     optional arguments:
       -h, --help            show this help message and exit
       -i, --id_as_name      Use transient digitizer ids as channel names, instead
                             of descriptive names
       -m MEASUREMENT_ID, --measurement_id MEASUREMENT_ID
                             The new measurement id
       -n MEASUREMENT_NUMBER, --measurement_number MEASUREMENT_NUMBER
                             The measurement number for the date from 00 to 99.
                             Used if no id is provided
       -t TEMPERATURE, --temperature TEMPERATURE
                             The temperature (in C) at lidar level, required if
                             using US Standard atmosphere
       -p PRESSURE, --pressure PRESSURE
                             The pressure (in hPa) at lidar level, required if
                             using US Standard atmosphere
       -D DARK_FILES, --dark_files DARK_FILES
                             Location of files containing dark measurements.
                             Use relative path and filename wildcars, see 'files'
                             parameter for example.
       -d, --debug           Print dubuging information.
       -s, --silent          Show only warning and error messages.
       --version             Show current version.
 Similarly, the ``licel2scc-depol`` program can be used to convert
 Licel files from Delta45 depolarization calibration measurements::
     A program to convert Licel binary files from depolarization calibration
     measurements to the SCC NetCDF format.
     positional arguments:
       parameter_file        The path to a parameter file linking licel and SCC
                             channels.
       plus45_string         Search string for plus 45 degree files (default '*.*')
       minus45_string        Search string for minus 45 degree files (default
                             '*.*')
     optional arguments:
       -h, --help            show this help message and exit
       -i, --id_as_name      Use transient digitizer ids as channel names, instead
                             of descriptive names
       -m MEASUREMENT_ID, --measurement_id MEASUREMENT_ID
                             The new measurement id
       -n MEASUREMENT_NUMBER, --measurement_number MEASUREMENT_NUMBER
                             The measurement number for the date from 00 to 99.
                             Used if no id is provided
       -t TEMPERATURE, --temperature TEMPERATURE
                             The temperature (in C) at lidar level, required if
                             using US Standard atmosphere
       -p PRESSURE, --pressure PRESSURE
                             The pressure (in hPa) at lidar level, required if
                             using US Standard atmosphere
       -d, --debug           Print dubuging information.
       -s, --silent          Show only warning and error messages.
       --version             Show current version.
 Usage in python code
 --------------------
 System class
 ~~~~~~~~~~~~
 To read data from a system, you need create a class that describes you system.
 This is very simple if your lidar data are in the Licel format, as you only need to specify
 the external file with the extra SCC parameters. You can use as an example the file ``cf_netcdf_parameters.py``:
 .. code-block:: python
    from licel import LicelLidarMeasurement
    import cf_netcdf_parameters
    class CfLidarMeasurement(LicelLidarMeasurement):
        extra_netcdf_parameters = cf_netcdf_parameters
 This code assumes that the ``cf_netcdf_parameters.py`` is in your python path.
 Using the class
 ~~~~~~~~~~~~~~~
 Once you have made the above setup you can start using it. The best way to understand how
 it works is through an interactive shell (I suggest [ipython](http://ipython.org/)).
 In the following example I use the cf_raymetrics setup:
 .. code-block:: python
    import glob  # This is needed to read a list of filenames
    import cf_lidar
    # Go to the folder where you files are stored
    cd /path/to/lidar/files
    # Read the filenames
    files  = glob.glob("*") # The * reads all the files in the folder.
    # Read the files
    my_measurement = cf_lidar.CfLidarMeasurement(files)
    # Now the data have been read, and you have a measurement object to work with:
    # See what channels are present
    print(my_measurement.channels)
    # Quicklooks of all the channels
    my_measurements.plot()
 Converting to SCC format
 ~~~~~~~~~~~~~~~~~~~~~~~~
 There are some extra info you need to put in before converting to SCC format, "Measurement_ID", "Temperature", "Pressure":
 .. code-block:: python
    my_measurement.info["Measurement_ID"] = "20101229op00"
    my_measurement.info["Temperature"] = "14"
    my_measurement.info["Pressure"] = "1010"
 You can use standard values of temperature and pressure by just calling:
 .. code-block:: python
     my_measurement.get_PT()
 You can specify the standard values by overriding your system's ``get_PT`` method:
 .. code-block:: python
    from licel import LicelLidarMeasurement
    import cf_netcdf_parameters
    class CfLidarMeasurement(LicelLidarMeasurement):
        extra_netcdf_parameters = cf_netcdf_parameters
        def get_PT():
            self.info['Temperature'] = 25.0
            self.info['Pressure'] = 1020.0
 If you have an external source of temperature and pressure information (a meteorological station) you can automate
 this by reading the appropriate code in the ``get_PT`` method .
 After you have used this extra input, you save the file using this command:
 .. code-block:: python
    my_measurement.save_as_SCC_netcdf("filename")
 where you change the output filename to the filename you want to use.

Mercurial > public > atmospheric_lidar / annotate

docs/introduction.rst@ab21bd91bc09 (annotated)

docs/introduction.rst