Set root_data in config file

README.md

@@ -6,10 +6,17 @@ Collocate submesoscale fronts to phytoplankton levels using satellite imagery
 
 - Download: Scripts for downloading data
 - lib: Reusable code. Scripts for defining databases
-- Compute: The actual code that does stuff. Each python script is accompanied
-  by a shell script to set the python environnement and launch it.
+- Compute: Process data, compute diagnostics,... Each python script is accompanied
+  by a shell script to set the python environnement and launch it. If not, ./launch_python.py
+  can be used.
 - Plots: Plotting scripts
 
+The root directory containing data has to be specified in the file `lib/conf.ini` as
+``` py
+[main]
+root_data: '/...'
+```
+
 
 ## Requirements
     

lib/__init__.py

 """General global variables."""
 
+import configparser
 import os
 from os import path
 
-from pathlib import Path
 
 import argparse
 import re
+# Read config file
+_config = configparser.ConfigParser()
+_config_file = path.join(path.dirname(__file__), 'conf.ini')
+if not path.isfile(_config_file):
+    raise RuntimeError("Missing configuration file lib/conf.ini")
 
+_config.read(_config_file)
 
-root = path.join(Path.home(), 'Documents/Work/Fronts')
-root_data = path.join(Path.home(), 'Documents/Work/Data')
+root_data = _config.get('main', 'root_data')
+if not path.isdir(root_data):
+    raise NameError(f"root_data '{root_data}' is not a valid directory.")
 root_plot = path.join(root_data, 'Plots')
 
 box_lat = [36., 41.]