Installation.md

@@ -2,22 +2,41 @@
 
 This package requires pip3, Python 3, GDAL, OTB and [Sen2Cor](http://step.esa.int/main/third-party-plugins-2/sen2cor/).
 
-Note: The current version of sen2chain is not available on Windows.
+Note: The current version of sen2chain is not available on Windows (yet).
 
 ### Prerequisites
 
-pip3, GDAL and OTB
+GDAL
 
 ```
-sudo apt install gdal-bin libgdal-dev python3-gdal otb-bin python3-otb python3-pip
+sudo apt install gdal-bin libgdal-dev python3-gdal
 ```
-In addition, all the dependencies you need to deploy for Sen2Chain are described in the [requirements](https://framagit.org/jebins/sen2chain/blob/master/requirements.txt).
+`Orfeo Toolbox (OTB) and its python bindings`
     
-As indicated in the [OTB installation](https://www.orfeo-toolbox.org/CookBook/Installation.html#linux-x86-64), do not forget to initialize the environment when you launch a new terminal with
+```
+wget https://www.orfeo-toolbox.org/packages/OTB-6.6.1-Linux64.run
+    chmod +x OTB-6.6.1-Linux64.run
+    ./OTB-6.6.1-Linux64.run
+```
+As indicated in the [OTB installation](https://www.orfeo-toolbox.org/CookBook/Installation.html#linux-x86-64), you need to modify some files to have functional OTB installation:
+
+* To use Python3 you need in the file otbenv.profile modify ``lib/python`` into ``lib/python3``, for variable PYTHONPATH
+
+* You need to add a symlink to libpython3.5m.so.rh-python35-1.0 to make it works. The method is described in the FAQ on the OTB installation page. Note that you can create this symlink regardless of your version of Python3 by pointing to the file libpython3.Xm.so..
+
+* Finally, you must initialize the environment each time you launch a terminal with
 
 ```
 source otbenv.profile
 ```
+You can also indicate in your user's .profile the path to ``otbenv.profile`` (example : ``source /home/user/OTB-6.6.0-Linux64/otbenv.profile``)
+
+Then you can install Python Numpy for OTB bindings
+
+```
+sudo apt install python3-numpy
+```
+
 Sen2Cor
 
 ```