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comparison: readme.rst

readme.rst

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1 Basic instructions 1 Overview
2 ================== 2 ========
3 3
4 These classes can be used to handle lidar input data. They are still in a very initial stage. There are many features probably not working, but they work for some specific tasks. They work with Licel input files (and also with the Raymetrics modified format). 4 This package provides utilities to handle raw (atmospheric) lidar input data.
5 The main format supported are Licel binary files (including the Raymetrics modified format).
6
7 The package provides a single command line tool, called licel2scc that can convert Licel binary files to the
8 EARLINET's Single Calculus Chain NetCDF format.
5 9
6 10
7 Set up 11 Using it as a Licel to SCC converter
8 ------ 12 ====================================
9 13
10 Parameter file 14 Parameter file
11 ~~~~~~~~~~~~~~ 15 --------------
12 Before using the classes you need to setup some channel parameters, that are used when converting the lidar data to Single Calculus Chain format. 16 Before converting Licel binary to SCC format, you need to create a file linking Licel channels to SCC channels.
13 17
14 All the parameters are read from an external file stored in the same folder as the code. You can start by changing the file “cf_netcdf_parameters.py” that describe such parameters for the Clermont Ferrand lidar. 18 As an example, you can start by changing the file “cf_netcdf_parameters.py” that describe such
19 parameters for the Clermont Ferrand lidar.
15 20
21 Command line interface
22 ----------------------
23 The usage of the ``licel2scc`` program is described bellow::
24
25 usage: licel2scc [-h] [-i] [-m MEASUREMENT_ID] [-n MEASUREMENT_NUMBER]
26 [-t TEMPERATURE] [-p PRESSURE] [-d] [-s]
27 parameter_file [directory] [search_string]
28
29 A program to convert LICEL binary files to the SCC NetCDF format.
30
31 positional arguments:
32 parameter_file The path to a parameter file linking licel and SCC
33 channels.
34 directory Directory containing licel files (default '.')
35 search_string Search string for files in directory (default '*.*')
36
37 optional arguments:
38 -h, --help show this help message and exit
39 -i, --id_as_name Use transient digitizer ids as channel names, instead
40 of descriptive names
41 -m MEASUREMENT_ID, --measurement_id MEASUREMENT_ID
42 The new measurement id
43 -n MEASUREMENT_NUMBER, --measurement_number MEASUREMENT_NUMBER
44 The measurement number for the date from 00 to 99.
45 Used if no id is provided
46 -t TEMPERATURE, --temperature TEMPERATURE
47 The temperature (in C) at lidar level, required if
48 using US Standard atmosphere
49 -p PRESSURE, --pressure PRESSURE
50 The pressure (in hPa) at lidar level, required if
51 using US Standard atmosphere
52 -d, --debug Print dubuging information.
53 -s, --silent Show only warning and error messages.
54
55
56 Usage in python code
57 --------------------
16 System class 58 System class
17 ~~~~~~~~~~~~ 59 ~~~~~~~~~~~~
18 The next thing you need to 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_raymetrics.py”: 60 To read data from a system, you need create a class that describes you system.
61 This is very simple if your lidar data are in the Licel format, as you only need to specify
62 the external file with the extra SCC parameters. You can use as an example the file “cf_netcdf_parameters.py”:
19 63
20 .. code:: python 64 .. code-block:: python
21 65 :caption: cf_lidar.py
22 from licel import LicelLidarMeasurement
23 import cf_netcdf_parameters
24
25 class CfLidarMeasurement(LicelLidarMeasurement):
26 extra_netcdf_parameters = cf_netcdf_parameters
27 66
67 from licel import LicelLidarMeasurement
68 import cf_netcdf_parameters
69
70 class CfLidarMeasurement(LicelLidarMeasurement):
71 extra_netcdf_parameters = cf_netcdf_parameters
72
73 This code assumes that the "cf_netcdf_parameters" is in your python path.
28 74
29 Using the class 75 Using the class
30 --------------- 76 ~~~~~~~~~~~~~~~
31 77
32 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: 78 Once you have made the above setup you can start using it. The best way to understand how
79 it works is through an interactive shell (I suggest [ipython](http://ipython.org/)).
80 In the following example I use the cf_raymetrics setup:
33 81
34 .. code:: python 82 .. code-block:: python
35
36 import glob # This is needed to read a list of filenames
37 from lidar import cf_raymetrics #If you have saved the files in a directrory called “lidar”
38 83
39 # Go to the folder where you files are stored 84 import glob # This is needed to read a list of filenames
40 cd /path/to/lidar/files 85 import cf_lidar
41 86
42 # Read the filenames 87 # Go to the folder where you files are stored
43 files = glob.glob("*") # The * reads all the files in the folder. 88 cd /path/to/lidar/files
44 89
45 #Read the files 90 # Read the filenames
46 my_measurement = cf_raymetrics.CfLidarMeasurement(files) 91 files = glob.glob("*") # The * reads all the files in the folder.
47 92
48 #Now the data have been read, and you have a measurement object to work with: 93 # Read the files
49 # See what channels are present 94 my_measurement = cf_lidar.CfLidarMeasurement(files)
50 print my_measurement.channels
51 95
52 # Quicklooks of all the channels 96 # Now the data have been read, and you have a measurement object to work with:
53 my_measurements.plot() 97 # See what channels are present
98 print(my_measurement.channels)
54 99
100 # Quicklooks of all the channels
101 my_measurements.plot()
55 102
56 Converting to SCC format 103 Converting to SCC format
57 ------------------------ 104 ~~~~~~~~~~~~~~~~~~~~~~~~
58 105
59 There are some extra info you need to put in before converting to SCC format, "Measurement_ID", "Temperature", "Pressure": 106 There are some extra info you need to put in before converting to SCC format, "Measurement_ID", "Temperature", "Pressure":
60 107
61 .. code:: python 108 .. code-block:: python
62 109
63 my_measurement.info["Measurement_ID"] = "20101229op00" 110 my_measurement.info["Measurement_ID"] = "20101229op00"
64 my_measurement.info["Temperature"] = "14" 111 my_measurement.info["Temperature"] = "14"
65 my_measurement.info["Pressure"] = "1010" 112 my_measurement.info["Pressure"] = "1010"
66 113
67 You can use standard values of temperature and pressure by just calling: 114 You can use standard values of temperature and pressure by just calling:
68 115
69 .. code:: python 116 .. code-block:: python
70
71 my_measurement.get_PT()
72 117
73 The standard values can be changed in generic.py. Search the get_PT method and change of what is appropriate for your station. If you have an external source of temperature and pressure information (a meteorological station) you can automate this by overriding the get_PT method in your system"s class (in our example in the cf_raymetrics.py file). 118 my_measurement.get_PT()
119
120 You can specify the standard values by overriding your system's ``get_PT`` method:
121
122 .. code-block:: python
123 :caption: cf_lidar.py
124
125 from licel import LicelLidarMeasurement
126 import cf_netcdf_parameters
127
128 class CfLidarMeasurement(LicelLidarMeasurement):
129 extra_netcdf_parameters = cf_netcdf_parameters
130
131 def get_PT():
132 self.info['Temperature'] = 25.0
133 self.info['Pressure'] = 1020.0
134
135 If you have an external source of temperature and pressure information (a meteorological station) you can automate
136 this by reading the appropriate code in the ``get_PT`` method .
74 137
75 138
76 After you have used this extra input, you save the file using this command: 139 After you have used this extra input, you save the file using this command:
77 140
78 .. code:: python 141 .. code-block:: python
79
80 my_measurement.save_as_netcdf("filename")
81 142
82 where you change the filename to the filename you want to use. 143 my_measurement.save_as_netcdf("filename")
144
145 where you change the output filename to the filename you want to use.

EARLINET Repository: Atmospheric Lidar Package

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